[ 2204阅读 ] 题型专项 - 细节题
TPO-16 Trade and the Ancient Middle East
Paragraph 1: Trade was the mainstay of the urban economy in the Middle East, as caravans negotiated the surrounding desert, restricted only by access to water and by mountain ranges. This has been so since ancient times, partly due to the geology of the area, which is mostly limestone and sandstone, with few deposits of metallic ore and other useful materials Ancient demands for obsidian (a black volcanic rock useful for making mirrors and tools) led to trade with Armenia to the north, while jade for cutting tools was brought from Turkistan, and the precious stone lapis lazuli was imported from Afghanistan. One can trace such expeditions back to ancient Sumeria, the earliest known Middle Eastern civilization. Records show merchant caravans and trading posts set up by the Sumerians in the surrounding mountains and deserts of Persia and Arabia, where they traded grain for raw materials, such as timber and stones, as well as for metals and gems.
1. According to paragraph 1, why has trade been so important throughout the history of the Middle East
○The rare and valuable metals and stones found in Middle Eastern deserts have always been in high demand in surrounding areas.
○Growing conditions throughout the Middle East are generally poor, forcing Middle Eastern people to depend on imported grain.
○Many useful and decorative raw materials cannot be found naturally in the Middle East but are available from neighboring regions.
○Frequent travel, due to limited water supplies in the Middle East, created many opportunities for trade with neighboring societies.
S：why 细节题 问原因 trade important
Paragraph 2: Reliance on trade had several important consequences. Production was generally in the hands of skilled individual artisans doing piecework under the tutelage of a master who was also the shop owner. In these shops differences of rank were blurred as artisans and masters labored side by side in the same modest establishment, were usually members of the same guild and religious sect, lived in the same neighborhoods, and often had assumed (or real) kinship relationships. The worker was bound to the master by a mutual contract that either one could repudiate, and the relationship was conceptualized as one of partnership.
2. According to paragraph 2, how did Middle Eastern shop owners treat their workers?
○Workers were ranked according to their skill level, with the most-experienced artisans becoming partial owners of the shop.
○Shop owners treated different workers differently depending on how much the workers had in common with their masters.
○Workers were bound to their masters by unbreakable contracts that strictly defined the terms of their partnership.
○The shop owner worked alongside the workers and often considered them partner and members of the family.
S：how 细节题 问方式 shop owners treat their workers
Paragraph 4: The mercantile economy was also characterized by a peculiar moral stance that is typical of people who live by trade—an attitude that is individualistic, calculating, risk taking, and adaptive to circumstances. As among tribes people, personal relationships and a careful weighing of character have always been crucial in a mercantile economy with little regulation, where one's word is one's bond and where informal ties of trust cement together an international trade network. Nor have merchants and artisans ever had much tolerance for aristocratic professions of moral superiority, favoring instead an egalitarian ethic of the open market, where steady hard work, the loyalty of one's fellows, and entrepreneurial skill make all the difference. And, like the pastoralists, Middle Eastern merchants and artisans unhappy with their environment could simply pack up and leave for greener pastures—an act of self-assertion wholly impossible in most other civilizations throughout history.
3. According to paragraph 4, what choice did Middle Eastern merchants and artisans have that many other people have not had?
○If they were unhappy in the mercantile environment, they could draw on personal connections to find a different kind of work.
○They were allowed to assert their opinions without having to listen to aristocratic professions of moral superiority.
○Following the example of the pastoralists, they could demand, and receive, better working conditions.
○If they didn't like their environment, they could move somewhere else.
S：what choice 细节题 Middle Eastern merchants and artisans
Development of the Periodic Table
Paragraph 1: The periodic table is a chart that reflects the periodic recurrence of chemical and physical properties of the elements when the elements are arranged in order of increasing atomic number (the number of protons in the nucleus). It is a monumental scientific achievement, and its development illustrates the essential interplay between observation, prediction, and testing required for scientific progress. In the 1800's scientists were searching for new elements. By the late 1860's more than 60 chemical elements had been identified, and much was known about their descriptive chemistry. Various proposals were put forth to arrange the elements into groups based on similarities in chemical and physical properties. The next step was to recognize a connection between group properties (physical or chemical similarities) and atomic mass (the measured mass of an individual atom of an element). When the elements known at the time were ordered by increasing atomic mass, it was found that successive elements belonged to different chemical groups and that the order of the groups in this sequence was fixed and repeated itself at regular intervals. Thus when the series of elements was written so as to begin a new horizontal row with each alkali metal, elements of the same groups were automatically assembled in vertical columns in a periodic table of the elements. This table was the forerunner of the modern table.
4. According to paragraph 1, what pattern did scientists notice when the known elements were written in order of increasing atomic mass?
○The elements of the group of alkali metals were the first elements in the order of increasing atomic mass.
○Repetition of the same atomic masses for elements in different groups appeared.
○Elements with similar chemical properties appeared in the listing at regular intervals.
○Elements were chemically most similar to those just before and after them in the order.
S：what pattern 细节题 atomic mass
Paragraph 2: When the German chemist Lothar Meyer and (independently) the Russian Dmitry Mendeleyev first introduced the periodic table in 1869-70, one-third of the naturally occurring chemical elements had not yet been discovered. Yet both chemists were sufficiently farsighted to leave gaps where their analyses of periodic physical and chemical properties indicated that new elements should be located. Mendeleyev was bolder than Meyer and even assumed that if a measured atomic mass put an element in the wrong place in the table, the atomic mass was wrong. In some cases this was true. Indium, for example, had previously been assigned an atomic mass between those of arsenic and selenium. Because there is no space in the periodic table between these two elements, Mendeleyev suggested that the atomic mass of indium be changed to a completely different value, where it would fill an empty space between cadmium and tin. In fact, subsequent work has shown that in a periodic table, elements should not be ordered strictly by atomic mass. For example, tellurium comes before iodine in the periodic table, even though its atomic mass is slightly greater. Such anomalies are due to the relative abundance of the "isotopes" or varieties of each element. All the isotopes of a given element have the same number of protons, but differ in their number of neutrons, and hence in their atomic mass. The isotopes of a given element have the same chemical properties but slightly different physical properties. We now know that atomic number (the number of protons in the nucleus), not atomic mass number (the number of protons and neutrons), determines chemical behavior.
5. What reason does the author provide for the claim that Mendeleyev was bolder than Meyer?
○Mendeleyev corrected incorrect information Meyer had proposed.
○Mendeleyev assumed that some information believed to be true about the elements was incorrect.
○Mendeleyev argued that Meyer had not left enough gaps in the periodic table.
○Mendeleyev realized that elements were not ordered by atomic mass in the periodic table.
S：What reason 细节题 问原因 Mendeleyev was bolder than Meyer
6. According to paragraph 2, why did Mendeleyev suggest changing the atomic mass of indium?
○Because indium did not fit into the periodic table in the place predicted by its atomic mass.
○Because there was experimental evidence that the atomic mass that had been assigned to indium was incorrect.
○Because there was an empty space between cadmium and tin in the periodic table.
○Because the chemical properties of indium were similar to those of arsenic and selenium.
S：why 细节题 问原因 Mendeleyev suggest changing the atomic mass of indium
Paragraph 3: Mendeleyev went further than Meyer in another respect: he predicted the properties of six elements yet to be discovered. For example, a gap just below aluminum suggested a new element would be found with properties analogous to those of aluminum. Mendeleyev designated this element "eka-aluminum" (eka is the Sanskrit word for "next") and predicted its properties. Just five years later an element with the proper atomic mass was isolated and named gallium by its discoverer. The close correspondence between the observed properties of gallium and Mendeleye Vs predictions for eka-aluminum lent strong support to the periodic law. Additional support came in 1885 when eka-silicon, which had also been described in advance by Mendeleyev, was discovered and named germanium.
7. Paragraph 3 suggests that Mendeleyev predicted the properties of eka-aluminum on the basis of
○the atomic mass of aluminum
○the position of the gap in the periodic table that eka-aluminum was predicted to fill
○the similarity of eka-aluminum to the other five missing elements
○observation of the properties of gallium
S：suggests 细节题 Mendeleyev predicted eka-aluminum basis
Planets in Our Solar System
Paragraph 4: Other dimensions along which the two groups differ markedly are density and composition. The densities of the terrestrial planets average about 5 times the density of water, whereas the Jovian planets have densities that average only 1.5 times the density of water. One of the outer planets, Saturn, has a density of only 0.7 that of water, which means that Saturn would float in water. Variations in the composition of the planets are largely responsible for the density differences. The substances that make up both groups of planets are divided into three groups—gases, rocks, and ices— based on their melting points. The terrestrial planets are mostly rocks: dense rocky and metallic material, with minor amounts of gases. The Jovian planets, on the other hand, contain a large percentage of the gases hydrogen and helium, with varying amounts of ices: mostly water, ammonia, and methane ices.
8. Paragraph 4 mentions which of the following as a reason why terrestrial planets are dense?
○They are made up of three groups of substances.
○They are composed mainly of rocky and metallic materials.
○They contain more ice than Jovian planets.
○They contain relatively small amounts of water.
S：reason why 细节题 问原因 terrestrial dense
Paragraph 5: The Jovian planets have very thick atmospheres consisting of varying amounts of hydrogen, helium, methane, and ammonia. By comparison, the terrestrial planets have meager atmospheres at best. A planet's ability to retain an atmosphere depends on its temperature and mass. Simply stated, a gas molecule can "evaporate" from a planet if it reaches a speed known as the escape velocity. For Earth, this velocity is 11 kilometers per second. Any material, including a rocket, must reach this speed before it can leave Earth and go into space. The Jovian planets, because of their greater masses and thus higher surface gravities, have higher escape velocities (21-60 kilometers per second) than the terrestrial planets. Consequently, it is more difficult for gases to "evaporate" from them. Also, because the molecular motion of a gas depends on temperature, at the low temperatures of the Jovian planets even the lightest gases are unlikely to acquire the speed needed to escape. On the other hand, a comparatively warm body with a small surface gravity, like Earth's moon, is unable to hold even the heaviest gas and thus lacks an atmosphere. The slightly larger terrestrial planets Earth, Venus, and Mars retain some heavy gases like carbon dioxide, but even their atmospheres make up only an infinitesimally small portion of their total mass.
9. According to paragraph 5, which of the following statements is true of both Jovian and terrestrial planets?
○ The thicker the atmosphere, the smaller the planet’s mass
○ The more varied the gases in the atmosphere, the higher the temperature
○ The higher the surface gravity, the higher the escape velocity
○ The less the atmosphere contributes to the total mass, the lower the temperature
S：true 细节题 问原因 Jovian and terrestrial planets
10. According to paragraph 5, what is a major reason that Jovian planets have much thicker atmospheres than terrestrial planets do?
○ Jovian planets have lower surface gravities
○ Jovian planets have lower temperatures
○ Jovian planets have lower escape velocities
○Jovian planets’ gas molecules have higher average speeds
S：what reason 细节题 问原因 Jovian thicker atmospheres than terrestrial planets
11. Paragraph 5 supports which of the following statements about the ability of planets to retain gases?
○More-massive planets are less able to retain gases than less-massive ones.
○Planets are more likely to retain heavy gases than light gases.
○Jovian planets are unlikely to retain the lightest gases.
○Only terrestrial planets have been able to retain carbon dioxide.
S：which 细节题 问原因 the ability of planets to retain gases
Paragraph 6: The orderly nature of our solar system leads most astronomers to conclude that the planets formed at essentially the same time and from the same material as the Sun. It is hypothesized that the primordial cloud of dust and gas from which all the planets are thought to have condensed had a composition somewhat similar to that of Jupiter. However, unlike Jupiter, the terrestrial planets today are nearly void of light gases and ices. The explanation may be that the terrestrial planets were once much larger and richer in these materials but eventually lost them because of these bodies' relative closeness to the Sun, which meant that their temperatures were relatively high.
form out of 组成，建造
12. In calling the cloud of gas and dust from which the Sun and all the planets are thought to have condensed "primordial,' the author means that the cloud was
○immense in size
○composed of similar particles
○present at the very beginning of our solar system's formation
○created from a great variety of different materials
S：author means 目的题 primordial
13. According to paragraph 6, what is a possible explanation for the lack of light gases and ices on terrestrial planets?
○The location of terrestrial planets caused them to lose some of the materials they once contained.
○Terrestrial planets were formed much later than Jovian planets.
○The composition of terrestrial planets was different from that of Jupiter.
○Terrestrial planets were formed out of different material than the Sun was.
S：what 细节题 lack of light gases and ices
TPO-17 Europe's Early Sea Trade with Asia
Paragraph 1: In the fourteenth century, a number of political developments cut Europe's overland trade routes to southern and eastern Asia, with which Europe had had important and highly profitable commercial ties since the twelfth century. This development, coming as it did when the bottom had fallen out of the European economy, provided an impetus to a long-held desire to secure direct relations with the East by establishing a sea trade. Widely reported, if somewhat distrusted, accounts by figures like the famous traveler from Venice. Marco Polo, of the willingness of people in China to trade with Europeans and of the immensity of the wealth to be gained by such contact made the idea irresistible Possibilities for trade seemed promising, but no hope existed for maintaining the traditional routes over land A new way had to be found.
14. According to paragraph 1 why was it necessary to find a new way for European merchants to reach the East?
○People in China were finally ready to trade with Europeans
○The European economy was failing because there was no trade with the East
○Traditional ways of trading with the East had becomevery costly
○Commercial routes over land had become blocked because of political events
S：why 细节题 find a new way for European
Paragraph 2: The chief problem was technological: How were the Europeans to reach the East? Europe's maritime tradition had developed in the context of easily navigable seas—the Mediterranean, the Baltic, and. to a lesser extent, the North Sea between England and the Continent—not of vast oceans. New types of ships were needed, new methods of finding one's way, new techniques for financing so vast a scheme. The sheer scale of the investment it took to begin commercial expansion at sea reflects the immensity of the profits that such East-West trade could create Spices were the most sought-after commodities. Spices not only dramatically improved the taste of the European diet but also were used to manufacture perfumes and certain medicines. But even high-priced commodities like spices had to be transported in large bulk in order to justify the expense and trouble of sailing around the African continent all the way to India and China.
15. According to paragraph 2. what was the main difficulty Europeans had to overcome in order to develop a new way of trading with the East?
○Europeans were unwilling to invest in large-scale commercial ventures.
○Europeans lacked the means for navigating long distances across oceans.
○Europeans were unwilling to experiment with new business techniques.
○Europeans lacked knowledge about the commercial methods of other peoples.
S：what difficulty 细节题 a new way of trading with the East
Paragraph 3: The principal seagoing ship used throughout the Middle Ages was the galley, a long, low ship fitted with sails but driven primarily by oars. The largest galleys had as many as 50 oarsmen Since they had relatively shallow hulls, they were unstable when driven by sail or when on rough water: hence they were unsuitable for the voyage to the East. Even if they hugged the African coastline, they had little chance of surviving a crossing of the Indian Ocean Shortly after 1400. Shipbuilders began developing a new type of vessel properly designed to operate in rough, open water: the caravel. It had a wider and deeper hull than the galley and hence could carry more cargo: increased stability made it possible to add multiple masts and sails. In the largest caravels, two main masts held large square sails that provided the bulk of the thrust driving the ship forward, while a smaller forward mast held a triangular-shaped sail, called a lateen sail, which could be moved into a variety of positions to maneuver the ship.
16. According to paragraph 3, what did the lateen sail contribute to the caravel as a sailing ship?
○It provided stability for the front part of the ship.
○It made it possible for the hull to be wider and deeper.
○It added considerably to the speed of the wind-driven ship.
○It improved the capacity of the ship to be guided.
S：what contribute 细节题 lateen sail caravel
Paragraph 4: The astrolabe had long been the primary instrument for navigation, having been introduced in the eleventh century. It operated by measuring the height of the Sun and the fixed stars: by calculating the angles created by these points, it determined the degree of latitude at which one stood (The problem of determining longitude, though, was not solved until the eighteenth century.) By the early thirteenth century. Western Europeans had also developed and put into use the magnetic compass, which helped when clouds obliterated both the Sun and the stars. Also beginning in the thirteenth century, there were new maps refined by precise calculations and the reports of sailors that made it possible to trace one's path with reasonable accuracy. Certain institutional and practical norms had become established as well. A maritime code known as the Consulate of the Sea. which originated in the western Mediterranean region in the fourteenth century, won acceptance by a majority of sea goers as the normative code for maritime conduct; it defined such matters as the authority of a ship's officers, protocols of command, pay structures, the rights of sailors, and the rules of engagement when ships met one another on the sea-lanes. Thus by about 1400 the key elements were in place to enable Europe to begin its seaward adventure.
17. According to paragraph 4, which of the following is true of the maritime code developed in Europe in the fourteenth century?
○It mapped out lanes in the seas for trading ships to follow.
○It defined the ways in which people should behave at sea.
○It replaced an earlier code that could not be adapted to the sea trade with the East.
○It gave instructions on how to navigate a ship.
S：which true 细节题 maritime code
Animal Signals in the Rain Forest
Paragraph 2: In the varied and constantly changing light environment of the forest, an animal must be able to send visual signals to members of its own species and at the same time avoid being detected by predators. An animal can hide from predators by choosing the light environment in which its pattern is least visible. This may require moving to different parts of the forest at different times of the day or under different weather conditions, or it may be achieved by changing color according to the changing light conditions. Many species of amphibians (frogs and toads) and reptiles (lizards and snakes) are able to change their color patterns to camouflage themselves. Some also signal by changing color. The chameleon lizard has the most striking ability to do this. Some chameleon species can change from a rather dull appearance to a full riot of carnival colors in seconds. By this means, they signal their level of aggression or readiness to mate.
18. According to paragraph 2, what is problematic about an animal's sending visual signals to members of its own species?
○Signs that make an animal visible to its species also make it visible to predators.
○An animal that changes color to avoid predators can confuse members of its species.
○Changing light may require an animal to move beyond the visual range of other members.
○The animal may mistakenly signal aggression when it meant to signal readiness to mate.
S：what problematic 细节题 sending visual signals
Paragraph 3: Other species take into account the changing conditions of light by performing their visual displays only when the light is favorable. A male bird of paradise may put himself in the limelight by displaying his spectacular plumage in the best stage setting to attract a female. Certain butterflies move into spots of sunlight that have penetrated to the forest floor and display by opening and closing their beautifully patterned wings in the bright spotlights They also compete with each other for the best spot of sunlight.
19. According to paragraph 3, butterflies move into spots of sunlight in order to
○warm their wings in order to open them
○compete with each other
○take advantage of favorable light conditions on the forest floor
○imitate birds of paradise
Paragraph 4: Very little light filters through the canopy of leaves and branches in a rain forest to reach ground level—or close to the ground—and at those levels the yellow-to-green wavelengths predominate. A signal might be most easily seen if it is maximally bright. In the green-to yellow lighting conditions of the lowest levels of the forest, yellow and green would be the brightest colors, but when an animal is signaling, these colors would not be very visible if the animal was sitting in an area with a yellowish or greenish background. The best signal depends not only on its brightness but also on how well it contrasts with the background against which it must be seen. In this part of the rain forest, therefore, red and orange are the best colors for signaling, and they are the colors used in signals by the ground-walking Australian brush turkey. This species, which lives in the rain forests and scrublands of the east coast of Australia, has a brown to-black plumage with bare, bright-red skin on the head and neck and a neck collar of orange-yellow loosely hanging skin. During courtship and aggressive displays, the turkey enlarges its colored neck collar by inflating sacs in the neck region and then flings about a pendulous part of the colored signaling apparatus as it utters calls designed to attract or repel. This impressive display is clearly visible in the light spectrum illuminating the forest floor.
20. According to paragraph 4, what is true about light that reaches ground level?
○It reveals only the yellow and green colors animals use to signal each other.
○It reflects the yellow and green colors to make the floor as bright as sunshine.
○It camouflages animals whose natural colors are yellow and green.
○It consists mostly of yellow-to-green wavelengths.
S：what is true 细节题 light that reaches ground level
Symbiotic Relationships
Paragraph 2: Parasitism is a kind of predator-prey relationship in which one organism, the parasite, derives its food at the expense of its symbiotic associate, the host. Parasites are usually smaller than their hosts. An example of a parasite is a tapeworm that lives inside the intestines of a larger animal and absorbs nutrients from its host. Natural selection favors the parasites that are best able to find and feed on hosts. At the same time, defensive abilities of hosts are also selected for. As an example, plants make chemicals toxic to fungal and bacterial parasites, along with ones toxic to predatory animals (sometimes they are the same chemicals). In vertebrates, the immune system provides a multiple defense against internal parasites.
21. According to paragraph 2. which of the following is true of the action of natural selection on hosts and parasites?
○Hosts benefit more from natural selection than parasites do.
○Both aggression in predators and defensive capacities in hosts are favored for species survival.
○The ability to make toxic chemicals enables a parasite to find and isolate its host.
○Larger size equips a parasite to prey on smaller host organisms.
S：which true 细节题 natural selection on hosts and parasites
Paragraph 3: At times, it is actually possible to watch the effects of natural selection in host-parasite relationships. For example, Australia during the 1940 s was overrun by hundreds of millions of European rabbits. The rabbits destroyed huge expanses of Australia and threatened the sheep and cattle industries. In 1950, myxoma virus, a parasite that affects rabbits, was deliberately introduced into Australia to control the rabbit population. Spread rapidly by mosquitoes, the virus devastated the rabbit population. The virus was less deadly to the offspring of surviving rabbits, however, and it caused less and less harm over the years. Apparently, genotypes (the genetic make-up of an organism) in the rabbit population were selected that were better able to resist the parasite. Meanwhile, the deadliest strains of the virus perished with their hosts as natural selection favored strains that could infect hosts but not kill them. Thus, natural selection stabilized this host-parasite relationship.
22. Which of the following can be concluded from the discussion in paragraph 3 about the Australian rabbit population?
○Human intervention may alter the host, the parasite. and the relationship between them.
○The risks of introducing outside organisms into a biological community are not worth the benefits.
○Humans should not interfere in host-parasite relationships.
○Organisms that survive a parasitic attack do so in spite of the natural selection process.
S：which concluded 细节题 Australian rabbit population
Paragraph 5: The third type of symbiosis, mutualism, benefits both partners in the relationship Legume plants and their nitrogen-fixing bacteria, and the interactions between flowering plants and their pollinators, are examples of mutualistic association. In the first case, the plants provide the bacteria with carbohydrates and other organic compounds, and the bacteria have enzymes that act as catalysts that eventually add nitrogen to the soil, enriching it. In the second case, pollinators (insects, birds) obtain food from the flowering plant, and the plant has its pollen distributed and seeds dispersed much more efficiently than they would be if they were carried by the wind only. Another example of mutualism would be the bull's horn acacia tree, which grows in Central and South America. The tree provides a place to live for ants of the genus Pseudomyrmex. The ants live in large, hollow thorns and eat sugar secreted by the tree. The ants also eat yellow structures at the tip of leaflets: these are protein rich and seem to have no function for the tree except to attract ants. The ants benefit the host tree by attacking virtually anything that touches it. They sting other insects and large herbivores (animals that eat only plants) and even clip surrounding vegetation that grows near the tree. When the ants are removed, the trees usually die, probably because herbivores damage them so much that they are unable to compete with surrounding vegetation for light and growing space.
23. According to paragraph 5, the relationship between legumes and bacteria benefits the soil by
○adding enriching carbohydrates
○speeding the decay of organic matter
○destroying enzymes that pollute it
○contributing nitrogen to it
S： 细节题 egumes and bacteria benefits soil
TPO-18 Industrialization in the Netherlands and Scandinavia
Paragraph 1: While some European countries, such as England and Germany, began to industrialize in the eighteenth century, the Netherlands and the Scandinavian countries of Denmark, Norway, and Sweden developed later. All four of these countries lagged considerably behind in the early nineteenth century. However, they industrialized rapidly in the second half of the century, especially in the last two or three decades. In view of their later start and their lack of coal—undoubtedly the main reason they were not among the early industrializers—it is important to understand the sources of their success.
24. Paragraph 1 supports which of the following ideas about England and Germany?
○ They were completely industrialized by the start of the nineteenth century.
○ They possessed plentiful supplies of coal.
○ They were overtaken economically by the Netherlands and Scandinavia during the early nineteenth century.
○ They succeeded for the same reasons that the Netherlands and Scandinavia did.
S： 细节题 ideas about England and Germany
Paragraph 2: All had small populations. At the beginning of the nineteenth century, Denmark and Norway had fewer than 1 million people, while Sweden and the Netherlands had fewer than 2.5 million inhabitants. All exhibited moderate growth rates in the course of the century (Denmark the highest and Sweden the lowest), but all more than doubled in population by 1900. Density varied greatly. The Netherlands had one of the highest population densities in Europe, whereas Norway and Sweden had the lowest Denmark was in between but closer to the Netherlands.
Paragraph 3: Considering human capital as a characteristic of the population, however, all four countries were advantaged by the large percentages of their populations who could read and write. In both 1850 and 1914, the Scandinavian countries had the highest literacy rates in Europe, or in the world, and the Netherlands was well above the European average. This fact was of enormous value in helping the national economies find their niches in the evolving currents of the international economy.
25. According to paragraphs 2 and 3, which of the following contributed significantly to the successful economic development of the Netherlands and of Scandinavia?
○ The relatively small size of their populations
○ The rapid rate at which their populations were growing
○ The large amount of capital they had available for investment
○ The high proportion of their citizens who were educated
S： 细节题 successful Netherlands and of Scandinavia
Paragraph 6: The key factor in the success of these countries (along with high literacy, which contributed to it) was their ability to adapt to the international division of labor determined by the early industrializers and to stake out areas of specialization in international markets for which they were especially well suited. This meant a great dependence on international commerce, which had notorious fluctuations; but it also meant high returns to those factors of production that were fortunate enough to be well placed in times of prosperity. In Sweden exports accounted for 18 percent of the national income in 1870, and in 1913, 22 percent of a much larger national income. In the early twentieth century, Denmark exported 63 percent of its agricultural production: butter, pork products, and eggs. It exported 80 percent of its butter, almost all to Great Britain, where it accounted for 40 percent of British butter imports.
depend v. 依赖;依靠;取决(于);指望;有赖(于)
26. According to paragraph 6, a major problem with depending heavily on international markets was that they
○ lacked stability
○ were not well suited to agricultural products
○ were largely controlled by the early industrializers
○ led to slower growth of local industries
S： 细节题 major problem
27. According to paragraph 6, what advantage could a country gain from being heavily involved in international commerce?
○ A steadily rising national income
○ Greater control over market fluctuations
○ High returns when things went well
○ A reduced need for imports
S： 细节题 gain
The mystery of yawning
Paragraph 1： According to conventional theory, yawning takes place when people are bored or sleepy and serves the function of increasing alertness by reversing, through deeper breathing, the drop in blood oxygen levels that are caused by the shallow breathing that accompanies lack of sleep or boredom. Unfortunately, the few scientific investigations of yawning have failed to find any connection between how often someone yawns and how much sleep they have had or how tired they are. About the closest any research has come to supporting the tiredness theory is to confirm that adults yawn more often on weekdays than at weekends, and that school children yawn more frequently in their first year at primary school than they do in kindergarten.
28. In paragragh1, what point does the author make about the evidence for the tiredness theory of yawning?
○ There is no scientific evidence linking yawning with tiredness.
○ The evidence is wide-ranging because it covers multiple age-groups.
○ The evidence is reliable because it was collected over a long period of time.
○ The evidence is questionable because the yawning patterns of children and adults should be different.
S： 细节题 evidence tiredness theory of yawning
Paragraph3: A completely different theory holds that yawning assists in the physical development of the lungs early in life, but has no remaining biological function in adults. It has been suggested that yawning and hiccupping might serve to clear out the fetuses airways. The lungs of a fetus secrete a liquid that mixes with its mother's amniotic fluid. Babies with congenital blockages that prevent this fluid from escaping from their lungs are sometimes born with deformed lungs. It might be that yawning helps to clear out the lungs by periodically lowering the pressure in them. According to this theory, yawning in adults is just a developmental fossil with no biological function. But, while accepting that not everything in life can be explained by Darwinian evolution, there are sound reasons for being skeptical of theories like this one, which avoid the issue of what yawning does for adults. Yawning is distracting, consumes energy and takes time. It is almost certainly doing something significant in adults as well as in fetuses. What could it be?
29. According to the developmental theory of yawning presented in paragraph 3, what is the role of yawning?
○ It caused hiccups, which aid in the development of the lungs.
○ It controls the amount of pressure the lungs place on other developing organs.
○ It prevents amniotic fluid from entering the lungs.
○ It removes a potentially harmful fluid from the lungs.
S： 细节题 what is the role
30. Paragraph 3 supports which of the following statements about the development theory of yawning?
○ The theory is attractive because it explains yawning from the perspective of Darwinian evolution.
○ The theory is unsatisfactory because it cannot explain the lung deformities of infants.
○ The theory is questionable because it does not explain why a useless and inconvenient behavior would continue into adulthood.
○ The theory is incomplete because it does not explain all the evolutionary stages in the development of yawning.
S： supports 推理题 development theory of yawning
Paragraph 4: The empirical evidence, such as it is, suggests an altogether different function for yawning—namely, that yawning prepares us for a change in activity level. Support for this theory came from a study of yawning behavior in everyday life. Volunteers wore wrist-mounted devices that automatically recorded their physical activity for up to two weeks: the volunteers also recorded their yawns by pressing a button on the device each time they yawned. The data showed that yawning tended to occur about 15 minutes before a period of increased behavioral activity. Yawning bore no relationship to sleep patterns, however. This accords with anecdotal evidence that people often yawn in situations where they are neither tired nor bored, but are preparing for impending mental and physical activity. Such yawning is often referred to as "incongruous" because it seems out of place, at least on the tiredness view: soldiers yawning before combat, musicians yawning before performing, and athletes yawning before competing. Their yawning seems to have nothing to do with sleepiness or boredom—quite the reverse—but it does precede a change in activity level.
31. The study of yawning behavior discussed in paragraph 4 supports which of the following conclusions?
○ Yawning is associated with an expectation of increased physical activity.
○ Yawning occurs more frequently when people are asked to record their yawning.
○ People tend to yawn about fifteen minutes before they become tired or bored.
○ Mental or physical stress tends to make people yawn.
S： supports 推理题 yawning behavior
Lightning
Paragraph 2: The separation of charged particles that forms in a storm cloud has a sandwich-like structure. Concentrations of positively charged particles develop at the top and bottom of the cloud, but the middle region becomes negatively charged. Recent measurements made in the field together with laboratory simulations offer a promising explanation of how this structure of charged particles forms. What happens is that small (millimeter-to centimeter-size) pellets of ice form in the cold upper regions of the cloud. When these ice pellets fall, some of them strike much smaller ice crystals in the center of the cloud. The temperature at the center of the cloud is about -15℃ or lower. At such temperatures, the collision between the ice pellets and the ice crystals causes electrical charges to shift so that the ice pellets acquire a negative charge and the ice crystals become positively charged. Then updraft wind currents carry the light, positively charged ice crystals up to the top of the cloud. The heavier negatively charged ice pellets are left to concentrate in the center. This process explains why the top of the cloud becomes positively charged, while the center becomes negatively charged. The negatively charged region is large: several hundred meters thick and several kilometers in diameter. Below this large, cold, negatively charged region, the cloud is warmer than -15℃, and at these temperatures, collisions between ice crystals and falling ice pellets produce positively charged ice pellets that then populate a small region at the base of the cloud.
32. According to paragraph2, what causes ice crystal to become positively charged?
○ Collisions with ice pellets
○ Collisions with negatively charged ice crystals at the base of the cloud
○ Becoming concentrated in the central region of the cloud
○ Forming at a temperature greater than -15℃
S： what 细节题 ice crystal to become positively charged
33. According to paragraph2, why are positively charged ice pellets produced in the lower part of the cloud?
○ Collisions between ice crystals and ice pellets increase in number in the lower part of the cloud.
○ The lower part of the cloud is smaller than the region above it.
○ More ice pellets than ice crystals reach the lower part of the cloud.
○ Temperature in the lower part of the cloud are warmer than -15℃.
S： why 细节题 ice pellets lower part of the cloud
Paragraph 3: Most lightning takes place within a cloud when the charge separation within the cloud collapses. However, as the storm cloud develops, the ground beneath the cloud becomes positively charged and lightning can take place in the form of an electrical discharge between the negative charge of the cloud and the positively charged ground. Lightning that strikes the ground is the most likely to be destructive, so even though it represents only 20 percent of all lightning, it has received a lot of scientific attention.
34. The author remarks that “Lightning that strikes the ground is the most likely to be destructive” in order to explain why
○ this form of lightning has been investigated so much
○ this form of lightning is not as common as lightning within a cloud
○ scientific understanding of this form of lightning is important
○ the buildup of positive charge on the ground beneath a storm cloud can have serious consequences
S： in order to 目的题
Paragraph 5: The formation of the channel is initiated when electrons surge from the cloud base toward the ground. When a stream of these negatively charged electrons comes within 100 meters of the ground it is met by a stream of positively charged particles that comes up from the ground. When the negatively and positively charged streams meet, a complete channel connecting the cloud and the ground is formed. The channel is only a few centimeters in diameter, but that is wide enough for electrons to follow the channel to the ground in the visible form of a flash of lightning. The stream of positive particles that meets the surge of electrons from the cloud often arises from a tall pointed structure such as a metal flagpole or a tower. That is why the subsequent lightning that follows the completed channel often strikes a tall structure.
35. According to paragraph5, which of the following is true of the stream of charged particles from the ground?
○ It prevents streams of electrons from the cloud from striking the ground.
○ It completes a channel that connects the storm cloud with the ground.
○ It produces a stream of electrons from the cloud.
○ It widens the path made by the initial stream of electrons from the cloud.
S：is true 细节题 the stream of charged particles from the ground
TPO-19 The Roman Army's Impact on Britain
Paragraph 1: In the wake of the Roman Empire's conquest of Britain in the first century A.D., a large number of troops stayed in the new province, and these troops had a considerable impact on Britain with their camps, fortifications, and participation in the local economy. Assessing the impact of the army on the civilian population starts from the realization that the soldiers were always unevenly distributed across the country. Areas rapidly incorporated into the empire were not long affected by the military. Where the army remained stationed, its presence was much more influential. The imposition of a military base involved the requisition of native lands for both the fort and the territory needed to feed and exercise the soldiers' animals. The imposition of military rule also robbed local leaders of opportunities to participate in local government, so social development was stunted and the seeds of disaffection sown. This then meant that the military had to remain to suppress rebellion and organize government.
36. According to paragraph 1, the Roman army had the most influence on those areas of Britain that were
O conquered first
O near population centers
O used as military bases
O rapidly incorporated into the empire
S：细节题 most influence
37. According to paragraph 1, what effect did military occupation have on the local population?
O It encouraged more even distribution of the population and the settlement of previously undeveloped territory.
O It created discontent and made continuing military occupation necessary.
O It required local labor to construct forts and feed and exercise the soldiers’ animals.
O It provided local leaders with opportunities to participate in governance.
S：细节题 what effect
Paragraph 3: Each soldier received his pay, but in regions without a developed economy there was initially little on which it could be spent. The pool of excess cash rapidly stimulated a thriving economy outside fort gates. Some of the demand for the services and goods was no doubt fulfilled by people drawn from far afield, but some local people certainly became entwined in this new economy. There was informal marriage with soldiers, who until AD 197 were not legally entitled to wed, and whole new communities grew up near the forts. These settlements acted like small towns, becoming centers for the artisan and trading populations.
38. According to paragraph 3, how did the soldiers meet their needs for goods and services?
O Their needs were met by the army, and all of their economic transactions took place within the fort.
O Most of their needs were met by traveling tradespeople who visit the forts.
O During their days off, soldiers traveled to distant towns to make purchases.
O They bought what they needed from the artisans and traders in nearby towns.
S：细节题 how soldiers meet
Paragraph 4: The army also provided a means of personal advancement for auxiliary soldiers recruited from the native peoples, as a man obtained hereditary Roman citizenship on retirement after service in an auxiliary regiment. Such units recruited on an ad hoc (as needed) basis from the area in which they were stationed, and there was evidently large-scale recruitment within Britain. The total numbers were at least 12,500 men up to the reign of the emperor Hadrian (A.D. 117-138), with a peak around A.D. 80. Although a small proportion of the total population, this perhaps had a massive local impact when a large proportion of the young men were removed from an area. Newly raised regiments were normally transferred to another province from whence it was unlikely that individual recruits would ever return. Most units raised in Britain went elsewhere on the European continent, although one is recorded in Morocco. The reverse process brought young men to Britain, where many continued to live after their 20 to 25 years of service, and this added to the cosmopolitan Roman character of the frontier population. By the later Roman period, frontier garrisons (groups of soldiers) were only rarely transferred, service in units became effectively hereditary, and forts were no longer populated or maintained at full strength.
39. According to paragraph 4, which of the following is true of Britain’s auxiliary regiments of the Roman army?
O Membership in these regiments reached its highest point during the region of the emperor Hadrian.
O Most of the units recruited in Britain were sent to Morocco and other stations outside Europe.
O Soldiers served in the regiments for many years and after retirement generally stayed where they had been stationed.
O Most of the regiments stationed on the frontier were new units transferred from a neighboring province.
S：is true 细节题 Britain’s auxiliary regiments
Succession, Climax, and Ecosystems
Paragraph 2: Clements and other early ecologists saw almost lawlike regularity in the order of succession, but that has not been substantiated. A general trend can be recognized, but the details are usually unpredictable. Succession is influenced by many factors: the nature of the soil, exposure to sun and wind, regularity of precipitation, chance colonizations, and many other random processes.
succession n. 继承;一系列;继任;一连串;(尤指王位的)继承权;交替;更迭;连续的人(或事物)
40. According to paragraph 2, which of the following is a criticism of Clements’ view of succession?
O The principles of succession are more lawlike than Clements thought they are.
O More evidence is needed to establish Clements’ predictions about succession.
O The details of succession are affected by random processes.
O Many of the factors that determine which plants will grow in an environment, such as the nature of the soil and the exposure to sun, do not change at all.
S：is true 细节题 criticism Clements
Paragraph 4: For Clements, the climax was a "superorganism," an organic entity. Even some authors who accepted the climax concept rejected Clements' characterization of it as a superorganism, and it is indeed a misleading metaphor. An ant colony may be legitimately called a superorganism because its communication system is so highly organized that the colony always works as a whole and appropriately according to the circumstances. But there is no evidence for such an interacting communicative network in a climax plant formation. Many authors prefer the term "association" to the term "community" in order to stress the looseness of the interaction.
41. According to paragraph 4, why do many authors prefer the term “association” to “community” when describing a climax plant formation?
O Because the term “association” does not suggest the presence of a tight network involving interactive communication.
O Because the term “association” indicates that the grouping is not necessarily beneficial to all members.
O Because the term “community” indicates continuing dynamic development that a climax formation does not have.
O Because the term “community” suggests an organization that has been designed for a specific purpose.
S：why prefer 细节题 问原因 association climax plant formation
Paragraph 5: Even less fortunate was the extension of this type of thinking to include animals as well as plants. This resulted in the "biome," a combination of coexisting flora and fauna. Though it is true that many animals are strictly associated with certain plants, it is misleading to speak of a "spruce-moose biome," for example, because there is no internal cohesion to their association as in an organism. The spruce community is not substantially affected by either the presence or absence of moose. Indeed, there are vast areas of spruce forest without moose. The opposition to the Clementsian concept of plant ecology was initiated by Herbert Gleason, soon joined by various other ecologists. Their major point was that the distribution of a given species was controlled by the habitat requirements of that species and that therefore the vegetation types were a simple consequence of the ecologies of individual plant species.
42. In paragraph 5, the author challenges the idea of a “biome” by noting that
O there are usually no very strong connections among the plants and animals living in a place
O plants and animals respond in the same way to the same circumstances
O particular combinations of flora and fauna do not generally come about purely by chance
O some animals are dependent on specific kinds of plants for food
S 细节题 challenges “biome”
43. According to paragraph 5, Gleason’s opposition to the Clementsian views of plant ecology was based on the claim that plant species grow in places where
O they can enter into mutually beneficial relationships with other species
O conditions suit them, regardless of whether particular other species are present
O habitats are available for a wide variety of plant and animal species
O their requirements are met, and those of most other species are not
S 细节题 challenges “biome”Gleason’s opposition
Paragraph 6: With "climax," "biome," "superorganism," and various other technical terms for the association of animals and plants at a given locality being criticized, the term "ecosystem" was more and more widely adopted for the whole system of associated organisms together with the physical factors of their environment. Eventually, the energy-transforming role of such a system was emphasized. Ecosystems thus involve the circulation, transformation, and accumulation of energy and matter through the medium of living things and their activities. The ecologist is concerned primarily with the quantities of matter and energy that pass through a given ecosystem, and with the rates at which they do so.
44. According to paragraph 6, what did ecologists mainly study when the ecosystem concept was the dominant paradigm?
O The physical factors present in different environments
O The typical activities of animals and the effect of those activities on plants
O The rates at which ecosystems changed from one kind to another
O The flow of energy and matter through ecosystems
S 细节题 ecosystem mainly study
Discovering the Ice Ages
Paragraph 1: In the middle of the nineteenth century, Louis Agassiz, one of the first scientists to study glaciers, immigrated to the United States from Switzerland and became a professor at Harvard University, where he continued his studies in geology and other sciences. For his research, Agassiz visited many places in the northern parts of Europe and North America, from the mountains of Scandinavia and New England to the rolling hills of the American Midwest. In all these diverse regions, Agassiz saw signs of glacial erosion and sedimentation. In flat plains country, he saw moraines (accumulations of earth and loose rock that form at the edges of glaciers) / that reminded him of / the terminal moraines / found at the end of valley glaciers in the Alps. The heterogeneous material of the drift (sand, clay, and rocks deposited there) convinced him of its glacial origin.
45. According to paragraph 1, what persuaded Louis Agassiz that glaciation in the past had been widespread?
O Geologic differences between mountain valleys and flat plains
O The presence of similar glacial material in many different regions
O Geologic research on mountain glaciers in the Alps
O Evidence of regional differences in the drift caused by glacial erosion
S what persuaded 细节题 Louis Agassiz past widespread
Paragraph 3: It soon became clear that there were multiple glacial ages during the Pleistocene, with warmer interglacial intervals between them. As geologists mapped glacial deposits in the late nineteenth century, they became aware that there were several layers of drift, the lower ones corresponding to earlier ice ages. Between the older layers of glacial material were well-developed soils containing fossils of warm-climate plants. These soils were evidence that the glaciers retreated as the climate warmed. By the early part of the twentieth century, scientists believed that four distinct glaciations had affected North America and Europe during the Pleistocene epoch.
46. According to paragraph 3, what did geologists conclude as a result of finding well-developed soils containing warm-climate plant fossils between layers of glacial drift?
O There had been only one warm period before the Pleistocene epoch.
O There had been multiple periods of mild weather between ice ages.
O Several glacial periods occurred after the Pleistocene epoch.
O Some earlier epochs were warmer thant the Pleistocene.
S what conclude 细节题 soils warm-climate plant fossils
Paragraph 4: This idea was modified in the late twentieth century, when geologists and oceanographers examining oceanic sediment found fossil evidence of warming and cooling of the oceans. Ocean sediments presented a much more complete geologic record of the Pleistocene than continental glacial deposits did. The fossils buried in Pleistocene and earlier ocean sediments were of foraminifera—small, single-celled marine organisms that secrete shells of calcium carbonate, or calcite. These shells differ in their proportion of ordinary oxygen (oxygen-16) and the heavy oxygen isotope (oxygen-18). The ratio of oxygen-16 to oxygen-18 found in the calcite of a foraminifer's shell depends on the temperature of the water in which the organism lived. Different ratios in the shells preserved in various layers of sediment reveal the temperature changes in the oceans during the Pleistocene epoch.
47. According to paragraph 3 and 4, scientists modified their theory about the exact number of glaciations because of evidence obtained from
O ocean sediments
O interglacial soils
O glacial deposits
O air samples
48. According to paragraph 4, scientists use foraminifera shells to learn about Pleistocene ocean conditions by
O measuring the amount of calcium carbonate present in the shells
O determining the proportion of shell in each layer of sediment
O comparing shells deposited during the Pleistocene with those buried earlier
O calculating the relative quantity of two oxygen isotopes in the calcite
S 细节题 foraminifera shells
Paragraph 5: Isotopic analysis of shells allowed geologists to measure another glacial effect. They could trace the growth and shrinkage of continental glaciers, even in parts of the ocean where there may have been no great change in temperature—around the equator, for example. The oxygen isotope ratio of the ocean changes as a great deal of water is withdrawn from it by evaporation and is precipitated as snow to form glacial ice. During glaciations, the lighter oxygen-16 has a greater tendency to evaporate from the ocean surface than the heavier oxygen-18 does. Thus, more of the heavy isotope is left behind in the ocean and absorbed by marine organisms. From this analysis of marine sediments, geologists have learned that there were many shorter, more regular cycles of glaciation and deglaciation than geologists had recognized from the glacial drift of the continents alone.
49. According to the passage, when did scientists begin to realize that more than one ice age had occurred ?
O In the mid nineteenth century
O In the late nineteenth century
O In the early twentieth century
O In the late twentieth century
S when 问时间 细节题 more than one ice age had occurred
TPO-20 Westward Migration
Paragraph 3: The West had plenty of attractions: the alluvial river bottoms, the fecund soils of the rolling forest lands, the black loams of the prairies were tempting to New England farmers working their rocky, sterile land and to southeastern farmers plagued with soil depletion and erosion. In 1820 under a new land law, a farm could be bought for $100. The continued proliferation of banks made it easier for those without cash to negotiate loans in paper money. Western Farmers borrowed with the confident expectation that the expanding economy would keep farm prices high, thus making it easy to repay loans when they fell due.
50. According to paragraph 3, what was the significance of the land law passed in 1820?
O It granted government-supported loans to farmers.
O It provided farmland at an affordable price.
O It required banks to offer loans to farmers.
O It enabled farmers to sell their land for a profit.
S 细节题 land law passed in 1820
Paragraph 4: Transportation was becoming less of a problem for those who wished to move west and for those who hand farm surpluses to send to market. Prior to 1815, western farmers who did not live on navigable waterways were connected to them only by dirt roads and mountain trails. Livestock could be driven across the mountains, but the cost of transporting bulky grains in this fashion was several times greater than their value in eastern markets. The first step toward an improvement of western transportation was the construction of turnpikes. These roads made possible a reduction in transportation costs and thus stimulated the commercialization of agriculture along their routes.
51. Paragraph 4 suggests that turnpikes affected farmers by
O making the price of grain uniform for both eastern and western farmers
O making western farm products more profitable than eastern farm products
O allowing farmers to drive their livestock across mountain trails
O allowing a greater number of farmers to sell their farm products in a commercial market
S suggests 问方式 细节题 turnpikes
Early Settlements in the Southwest Asia
Paragraph 4: The flotation samples from the excavations allowed botanists to study shifts in plant-collecting habits as if they were looking through a telescope at a changing landscape. Hundreds of tiny plant remains show how the inhabitants exploited nut harvests in nearby pistachio and oak forests. However, as the climate dried up, the forests retreated from the vicinity of the settlement. The inhabitants turned to wild cereal grasses instead, collecting them by the thousands, while the percentage of nuts in the diet fell. By 8200B.C., drought conditions were so severe that the people abandoned their long-established settlement, perhaps dispersing into smaller camps.
52. Paragraph 4 suggests that the people of Abu Hureyra abandoned their long-established settlement because
O the inhabitants had cleared all the trees from the forests
O wild cereal grasses took over pistachio and oak forests
O people wanted to explore new areas
O lack of rain caused food shortages
S suggests 问方式 细节题 Abu Hureyra abandoned settlement
Fossil Preservation
Paragraph 3: Many other processes may after the shell of a clam or snail and enhance its chances for preservation. Water containing dissolved silica, calcium carbonate, or iron may circulate through the enclosing sediment and be deposited in cavities such as marrow cavities and canals in bone once occupied by blood vessels and nerves. In such cases, the original composition of the bone or shell remains, but the fossil is made harder and more durable. This addition of a chemically precipitated substance into pore spaces is termed "permineralization."
53. Which of the following best explains the process of permineralization mentioned in paragraph 3?
O Water containing calcium carbonate circulates through a shell and deposits sediment.
O Liquid containing chemicals hardens an already existing fossil structure.
O Water passes through sediment surrounding a fossil and removes its chemical content.
O A chemical substance enters a fossil and changes its shape.
S best explains 问方式 细节题 permineralization mentioned
Paragraph 7: The probability that actual remains of soft tissue will be preserved is improved if the organism dies in an environment of rapid deposition and oxygen deprivation. Under such conditions, the destructive effects of bacteria are diminished. The Middle Eocene Messel Shale (from about 48 million years ago) of Germany accumulated in such an environment. The shale was deposited in an oxygen-deficient lake where lethal gases sometimes bubbled up and killed animals. Their remains accumulated on the floor of the lake and were then covered by clay and silt. Among the superbly preserved Messel fossils are insects with iridescent exoskeletons (hard outer coverings), frogs with skin and blood vessels intact, and even entire small mammals with preserved fur and soft tissue.
54. According to paragraph 7, how do environments containing oxygen affect fossil preservation?
O They increase the probability that soft-tissued organisms will become fossils.
O They lead to more bacteria production.
O They slow the rate at which clay and silt are deposited.
O They reduce the chance that animal remains will be preserved.
S how 问方式 细节题 oxygen affect