[ 2204阅读 ] 题型专项 - 推理题
TPO-11 Orientation and Navigation
Paragraph 1: To South Americans, robins are birds that fly north every spring. To North Americans, the robins simply vacation in the south each winter. Furthermore, they fly to very specific places in South America and will often come back to the same trees in North American yards the following spring. The question is not why they would leave the cold of winter so much as how they find their way around. The question perplexed people for years, until, in the 1950s, a German scientist named Gustave Kramer provided some answers and, in the process, raised new questions.
1. Which of the following can be inferred about bird migration from paragraph 1?
○ Birds will take the most direct migratory route to their new habitat.
○ The purpose of migration is to join with larger groups of birds.
○ Bird migration generally involves moving back and forth between north and south.
○ The destination of birds' migration can change from year to year.
S：inferred 推理题 bird migration 排除题方式
Paragraph 3: Early in his research, Kramer found that caged migratory birds became very restless at about the time they would normally have begun migration in the wild. Furthermore, he noticed that as they fluttered around in the cage, they often launched themselves in the direction of their normal migratory route. He then set up experiments with caged starlings and found that their orientation was, in fact, in the proper migratory direction except when the sky was overcast, at which times there was no clear direction to their restless movements. Kramer surmised, therefore, that they were orienting according to the position of the Sun. To test this idea, he blocked their view of the Sun and used mirrors to change its apparent position. He found that under these circumstances, the birds oriented with respect to the new "Sun." They seemed to be using the Sun as a compass to determine direction. At the time, this idea seemed preposterous. How could a bird navigate by the Sun when some of us lose our way with road maps? Obviously, more testing was in order.
Paragraph 4: So, in another set of experiments, Kramer put identical food boxes around the cage, with food in only one of the boxes. The boxes were stationary, and the one containing food was always at the same point of the compass. However, its position with respect to the surroundings could be changed by revolving either the inner cage containing the birds or the outer walls, which served as the background. As long as the birds could see the Sun, no matter how their surroundings were altered, they went directly to the correct food box. Whether the box appeared in front of the right wall or the left wall, they showed no signs of confusion. On overcast days, however, the birds were disoriented and had trouble locating their food box.
preposterous adj. 荒谬的;荒唐的;离奇古怪的;极不合情理的;怪诞的
2. Which of the following can be inferred from paragraph 4 about Kramer s reason for filling one food box and leaving the rest empty?
○ He believed the birds would eat food from only one box.
○ He wanted to see whether the Sun alone controlled the birds' ability to navigate toward the box with food.
○ He thought that if all the boxes contained food, this would distract the birds from following their migratory route.
○ He needed to test whether the birds preferred having the food at any particular point of the compass.
S：inferred 推理题 reason for filling one food box and leaving the rest empty
Begging by Nestlings
Paragraph 4: Given that predators can make it costly to beg for food, what benefit do begging nestlings derive from their communications? One possibility is that a noisy baby bird provides accurate signals of its real hunger and good health, making it worthwhile for the listening parent to give it food in a nest where several other offspring are usually available to be fed. If this hypothesis is true, then it follows that nestlings should adjust the intensity of their signals in relation to the signals produced by their nestmates, who are competing for parental attention. When experimentally deprived baby robins are placed in a nest with normally fed siblings, the hungry nestlings beg more loudly than usual—but so do their better-fed siblings, though not as loudly as the hungrier birds.
Paragraph 5: If parent birds use begging intensity to direct food to healthy offspring capable of vigorous begging, then parents should make food delivery decisions on the basis of their offsprings’ calls. Indeed, if you take baby tree swallows out of a nest for an hour feeding half the set and starving the other half, when the birds are replaced in the nest, the starved youngsters beg more loudly than the fed birds, and the parent birds feed the active beggars more than those who beg less vigorously.
nestling n. 雏鸟;未离巢的小鸟
intensity n. 强度;强烈;紧张;烈度;剧烈
3. It can be inferred from paragraphs 4 and 5 that parent songbirds normally do not feed
○ nestlings that are too weak to beg for food as vigorously as their nestmates
○ more than one hungry nestling during a single visit to the nest
○ offspring that were fed by the parents on the previous visit to the nest
○ nestlings that have been removed and then later put back into their nest
S：inferred 推理题 songbirds do not feed
TPO-12 Which Hand Did They Use?
Paragraph 1: We all know that many more people today are right-handed than left-handed. Can one trace this same pattern far back in prehistory? Much of the evidence about right-hand versus left-hand dominance comes from stencils and prints found in rock shelters in Australia and elsewhere, and in many Ice Age caves in France, Spain, and Tasmania. When a left hand has been stenciled, this implies that the artist was right-handed, and vice versa. Even though the paint was often sprayed on by mouth, one can assume that the dominant hand assisted in the operation. One also has to make the assumption that hands were stenciled palm downward—a left hand stenciled palm upward might of course look as if it were a right hand. Of 158 stencils in the French cave of Gargas, 136 have been identified as left, and only 22 as right; right-handedness was therefore heavily predominant.
stencil n. (印文字或图案用的)模板;(用模板印的)文字或图案
vice versa adv. 反之亦然，反过来也一样
versa 反之亦然
4. It can be inferred from paragraph 1 that even when paint was sprayed by mouth to make a hand stencil
○ there was no way to tell which hand was stenciled
○ the stenciled hand was the weaker hand
○ the stenciled hand was the dominant hand
○ artists stenciled more images of the dominant hand than they did of the weak
S：inferred 推理题 sprayed by mouth make a hand stencil
Paragraph 4: Fractures and other cut marks are another source of evidence. Right-handed soldiers tend to be wounded on the left. The skeleton of a 40- or 50-year-old Nabatean warrior, buried 2,000 years ago in the Negev Desert, Israel, had multiple healed fractures to the skull, the left arm, and the ribs.
5. Which of the following statements about fractures and cut marks can be inferred from paragraph 4?
○ Fractures and cut marks caused by right-handed soldiers tend to occur on the right side of the injured party's body.
○ The right arm sustains more injuries because, as the dominant arm, it is used more actively.
○ In most people, the left side of the body is more vulnerable to injury since it is not defended effectively by the dominant arm.
○ Fractures and cut marks on fossil humans probably occurred after death.
S：inferred 推理题 fractures and cut marks
Water in the Desert
Paragraph 1: Rainfall is not completely absent in desert areas, but it is highly variable. An annual rainfall of four inches is often used to define the limits of a desert. The impact of rainfall upon the surface water and groundwater resources of the desert is greatly influenced by landforms. Flats and depressions where water can collect are common features, but they make up only a small part of the landscape.
6. Which of the following statements about annual rainfall can be inferred from paragraph 1?
○Flat desert areas receive more annual rainfall than desert areas with mountains.
○Areas that receive more than four inches of rain per year are not considered deserts.
○Many areas receive less than four inches of annual rainfall, but only a few are deserts.
○Annual rainfall has no impact on the groundwater resources of desert areas.
S：inferred 推理题 annual rainfall
TPO-13 Types of Social Groups
Paragraph 2: People are bound within relationships by two types of bonds: expressive ties and instrumental ties. Expressive ties are social links formed when we emotionally invest ourselves in and commit ourselves to other people. Through association with people who are meaningful to us, we achieve a sense of security, love, acceptance, companionship, and personal worth. Instrumental ties are social links formed when we cooperate with other people to achieve some goal. Occasionally, this may mean working with instead of against competitors. More often, we simply cooperate with others to reach some end without endowing the relationship with any larger significance.
endow vt. (向学校等机构)捐钱，捐赠，资助;天生赋予
7. Which of the following can be inferred about instrumental ties from the author's mention of working with competitors in paragraph 2?
○ Instrumental ties can develop even in situations in which people would normally not cooperate.
○ Instrumental ties require as much emotional investment as expressive ties.
○ Instrumental ties involve security, love, and acceptance.
○ Instrumental ties should be expected to be significant.
S：inferred 推理题 instrumental ties working with competitors
Paragraph 3: Sociologists have built on the distinction between expressive and instrumental ties to distinguish between two types of groups: primary and secondary. A primary group involves two or more people who enjoy a direct, intimate, cohesive relationship with one another. Expressive ties predominate in primary groups; we view the people as ends in themselves and valuable in their own right. A secondary group entails two or more people who are involved in an impersonal relationship and have come together for a specific, practical purpose. Instrumental ties predominate in secondary groups; we perceive people as means to ends rather than as ends in their own right. Sometimes primary group relationships evolve out of secondary group relationships. This happens in many work settings. People on the job often develop close relationships with coworkers as they come to share gripes, jokes, gossip, and satisfactions.
evolve out of 进化出;从…逐渐形【发展】成
8. Which of the following can be inferred from the author's claim in paragraph 3 that primary group relationships sometimes evolve out of secondary group relationships?
○ Secondary group relationships begin by being primary group relationships.
○ A secondary group relationship that is highly visible quickly becomes a primary group relationship.
○ Sociologists believe that only primary group relationships are important to society.
○ Even in secondary groups, frequent communication serves to bring people into close relationships.
S：inferred 推理题 primary group evolve out of secondary group
Maya Water Problems
Paragraph 4: How did those dense southern Maya populations deal with the resulting water problem? It initially surprises us that many of their cities were not built next to the rivers but instead on high terrain in rolling uplands. The explanation is that the Maya excavated depressions, or modified natural depressions, and then plugged up leaks in the karst by plastering the bottoms of the depressions in order to create reservoirs, which collected rain from large plastered catchment basins and stored it for use in the dry season. For example, reservoirs at the Maya city of Tikal held enough water to meet the drinking water needs of about 10,000 people for a period of 18 months. At the city of Coba the Maya built dikes around a lake in order to raise its level and make their water supply more reliable. But the inhabitants of Tikal and other cities dependent on reservoirs for drinking water would still have been in deep trouble if 18 months passed without rain in a prolonged drought. A shorter drought in which they exhausted their stored food supplies might already have gotten them in deep trouble, because growing crops required rain rather than reservoirs.
9.What can be inferred from paragraph 4 about how residents of Tikal met their needs for water and food during most periods of drought?
○They depended upon water and food that had been stored for use during the dry season.
○They obtained drinking water and water for crop irrigation from Coba dikes.
○They located their population centers near a lake where water was available for drinking and watering crops.
○They moved locations every 18 months to find new croplands and water sources.
S：inferred 推理题 met their needs for water during most periods of drought
TPO-15 A Warm-Blooded Turtle
Paragraph 1: When it comes to physiology, the leatherback turtle is, in some ways, more like a reptilian whale than a turtle. It swims farther into the cold of the northern and southern oceans than any other sea turtle, and it deals with the chilly waters in a way unique among reptiles.
10. What can be inferred about whales from paragraph 1?
○They are considered by some to be reptiles.
○Their bodies are built in a way that helps them manage extremely cold temperatures.
○They are distantly related to leatherback turtles.
○They can swim farther than leatherback turtles.
S：inferred 推理题 whales
Glacier Formation
Paragraph2: Glaciers are open systems, with snow as the system’s input and meltwater as the system's main output. The glacial system is governed by two basic climatic variables: precipitation and temperature. For a glacier to grow or maintain its mass, there must be sufficient snowfall to match or exceed the annual loss through melting, evaporation, and calving, which occurs when the glacier loses solid chunks as icebergs to the sea or to large lakes. If summer temperatures are high for too long, then all the snowfall from the previous winter will melt. Surplus snowfall is essential for a glacier to develop. A surplus allows snow to accumulate and for the pressure of snow accumulated over the years to transform buried snow into glacial ice with a depth great enough for the ice to flow. Glaciers are sometimes classified by temperature as faster-flowing temperate glaciers or as slower-flowing polar glaciers.
11. Paragraph 2 implies that which of the following conditions produces the fastest moving glaciers?
○A climate characteristic of the polar regions
○A thick layer of ice in a temperate climate
○Long, warm summers
○Snow, firn, and ice that have been buried for several years
S：inferred 推理题 the fastest moving glaciers
TPO-16 Development of the Periodic Table
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.
comes before 在之前;被交付(审判等)
tellurium n. 碲
iodine n. 碘
farsighted adj. 有远见的;远视的；有先见之明的
anomalies n. 反常现象;异常事物
anomaly n. 异常;反常现象;异常事物
12. It can be inferred from paragraph 2 that tellurium comes before iodine in the periodic table even though tellurium's atomic mass is slightly greater because
○iodine is less common than tellurium
○both iodine and tellurium have no isotopes
○the chemical behavior of tellurium is highly variable
○the atomic number of tellurium is smaller than that of iodine
S：inferred 推理题 tellurium comes before iodine tellurium's atomic mass greater
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.
13. It can be inferred from paragraph 3 that the significance of the discovery of gallium was that it supported which of the following?
○The idea that aluminum was correctly placed in the periodic table.
○Mendeleyev's prediction that eka-silicon would be discovered next.
○The organizing principle of the periodic table.
○The idea that unknown elements existed.
S：inferred 推理题 significance of the discovery of gallium
TPO-17 Europe's Early Sea Trade with Asia
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.
14. It can be inferred from paragraph 2 that spices from Asia were desirable in Europe in the Middle Ages because they
○were easily transported in large quantities
○could not be produced in European countries
○could be traded for products such as perfumes and medicines
○were expected to increase in value over time
S：inferred 推理题 spices from Asia were desirable in Europe
Animal Signals in the Rain Forest
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.
15. Which of the following can be inferred from paragraph 4 about yellow and green colors compared with red and orange colors at the bottom of the forest?
○Yellow and green are better colors for signaling than red and orange colors.
○Orange and red are brighter colors than yellow and green.
○Yellow and green are likely to be more common in the background than red and orange.
○Orange and red colors do not contrast as well with the forest floor as yellow and green do
S：inferred 推理题 yellow and green compared with red and orange
Paragraph 5: Less colorful birds and animals that inhabit the rain forest tend to rely on forms of signaling other than the visual, particularly over long distances. The piercing cries of the rhinoceros hornbill characterize the Southeast Asian rain forest, as do the unmistakable calls of the gibbons. In densely wooded environments, sound is the best means of communication over distance because in comparison with light, it travels with little impediment from trees and other vegetation. In forests, visual signals can be seen only at short distances, where they are not obstructed by trees. The male riflebird exploits both of these modes of signaling simultaneously in his courtship display. The sounds made as each wing is opened carry extremely well over distance and advertise his presence widely. The ritualized visual display communicates in close quarters when a female has approached.
cries v. 哭;哭泣;呼喊;喊叫;呼叫;吠;发出刺耳的叫声;嗥叫 n. 叫喊；传闻 cry的第三人称单数
16. What can be inferred from paragraph 5 about the less colorful birds and animals that inhabit the forest?
○These species are less able to see color. and therefore they communicate with one another using nonvisual signals.
○These species generally live in less densely wooded environments than more colorful birds and animals do.
○The cries of these species do not carry as well over distances as the cries of more colorful birds and animals.
○These species depend more on nonvisual signals for communication because they are less visible in their environment.
S：inferred 推理题 less colorful birds and animals inhabit forest
Symbiotic Relationships
Paragraph 1: A symbiotic relationship is an interaction between two or more species in which one species lives in or on another species. There are three main types of symbiotic relationships: parasitism, commensalism, and mutualism. The first and the third can be key factors in the structure of a biological community; that is, all the populations of organisms living together and potentially interacting in a particular area.
17. Which of the following statements about commensalism can be inferred from paragraph 1?
○It excludes interactions between more than two species.
○It makes it less likely for species within a community to survive.
○Its significance to the organization of biological communities is small.
○Its role in the structure of biological populations is a disruptive one.
S：inferred 推理题 commensalism
TPO-18 Lightning
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.
18. Which of the following claims about lightning strikes can be inferred from paragraph 5?
○ During a lightning strike the diameter of the channel the electrons follow is considerably enlarged beyond a few centimeters.
○ A building is unlikely to be hit by lightning unless it is at least 100 meters tall.
○ A building is hit by a lightning strike because the building itself has first determined the path the lightening then takes to it.
○ The light of a lightning strike first appears at the point where the streams of negative and positive particles meet.
S：inferred 推理题 lightning strikes
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.
19. It can be inferred from paragraph 2 that part of the reason that the top of a storm cloud becomes positively charged is that
○ the top of the cloud is warmer than the middle of the cloud
○ the middle of the cloud is already occupied by positively charged particles
○ the negatively charged ice pellets are too heavy to be carried by the updrafts that move ice crystals
○ collisions between ice pellets in the top of the cloud produce mainly positively charged particles
S：inferred 推理题 he top of a storm becomes positively charged
TPO-19 Discovering the Ice Ages
Paragraph 2: The areas covered by this material were so vast that the ice that deposited it must have been a continental glacier larger than Greenland or Antarctica. Eventually, Agassiz and others convinced geologists and the general public that a great continental glaciation had extended the polar ice caps far into regions that now enjoy temperate climates. For the first time, people began to talk about ice ages. It was also apparent that the glaciation occurred in the relatively recent past because the drift was soft, like freshly deposited sediment. We now know the age of the glaciation accurately from radiometric dating of the carbon-14 in logs buried in the drift. The drift of the last glaciation was deposited during one of the most recent epochs of geologic time, the Pleistocene, which lasted from 1.8 million to 10,000 years ago. Along the east coast of the United States, the southern most advance of this ice is recorded by the enormous sand and drift deposits of the terminal moraines that form Long Island and Cape Cod.
20. It can be inferred from paragraph 2 that Agassiz and other geologists of his time were not able to determine
○ which geographic regions had been covered with ice sheets in the last ice age
○ the exact dates at which drifts had been deposited during the last ice age
○ the exact composition of the drifts laid during the last ice age
○ how far south along the east coast of the United States the ice had advanced during the last ice age
S：inferred 推理题 Agassiz not able to determine
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.
21. In can be inferred from paragraph 5 that foraminifera fossil shells containing calcite with high percentages of oxygen-16 were deposited at times when
Opolar ice extended as far as equatorial regions of land and sea
Oextensive glaciation was not occurring
Othere were no great increases in ocean temperature
Othere was heavy snowfall on continental glaciers
S：inferred 推理题 shells containing calcite oxygen-16
TPO-20 Westward Migration
Paragraph 1: The story of the westward movement of population in the United States is, in the main, the story of the expansion of American agriculture—of the development of new areas for the raising of livestock and the cultivation of wheat, corn, tobacco, and cotton. After 1815 improved transportation enabled more and more western farmers to escape a self-sufficient way of life and enter a national market economy. During periods when commodity prices were high, the rate of westward migration increased spectacularly. "Old America seemed to be breaking up and moving westward," observed an English visitor in 1817,during the first great wave of migration. Emigration to the West reached a peak in the 1830's. Whereas in 1810 only a seventh of the American people lived west of the Appalachian Mountains, by 1840 more than a third lived there.
prior to 之前;在前，居先
22. What can be inferred from paragraph 1 about western farmers prior to 1815?
OThey had limited their crop production to wheat, corn, tobacco, and cotton.
OThey were able to sell their produce at high prices.
OThey had not been successful in raising cattle.
OThey did not operate in a national market economy.
S：inferred 推理题 western farmers prior to 1815
Paragraph 5: Two other developments presaged the end of the era of turnpikes and started a transportation revolution that resulted in increased regional specialization and the growth of a national market economy. First came the steamboat; although flatboats and keelboats continued to be important until the 1850’s steamboats eventually superseded all other craft in the carrying of passengers and freight. Steamboats were not only faster but also transported upriver freight for about one tenth of what it had previously cost on hand-propelled keelboats. Next came the Erie Canal, an enormous project in its day, spanning about 350 miles. After the canal went into operation, the cost per mile of transporting a ton of freight from Buffalo to New York City declined from nearly 20 cents to less than 1 cent. Eventually, the western states diverted much of their produce from the rivers to the Erie Canal, a shorter route to eastern markets.
23. Which of the following can be inferred from paragraph 5 about flatboats and keelboats?
OThey ceased to be used as soon as the first turnpikes were built.
OThey were slower and more expensive to operate than steamboats.
OThey were used for long-distance but not for regional transportation.
OThey were used primarily on the Erie Canal.
S：inferred 推理题 flatboats and keelboats
Fossil Preservation
Paragraph 5: Another type of fossilization, known as carbonization, occurs when soft tissues are preserved as thin films of carbon. Leaves and tissue of soft-bodied organisms such as jellyfish or worms may accumulate, become buried and compressed, and lose their volatile constituents. The carbon often remains behind as a blackened silhouette.
24. Paragraph 5 suggests which of the following about the carbonization process?
OIt is completed soon after an organism dies.
OIt does not occur in hard-shell organisms.
OIt sometimes allows soft-tissued organisms to be preserved with all their parts.
OIt is a more precise process of preservation than is replacement.
S：suggests 推理题 carbonization process