A
I am an active playgoer 戏迷 and play-reader, and perhaps my best reason for editing this book is a hope of sharing（share sth with sb） my enthusiasm for the theater with others. To do this I have searched through dozens of plays to find the ones that I think best show the power and purpose of the short play.
Each play has a theme or central idea中心思想 which the playwright (剧作家) hopes to get across（get sth across 把...说清楚，使被传达） through dialogue and action. A few characters are used to create a single impression growing out of the theme. It is not my intention to point out 指出 the central theme中心主题 of each of the plays in this collection, for that would, indeed, ruin the pleasure of reading, discussing, and thinking about the plays and the effectiveness of the playwright. However, a variety of types is represented here. These include comedy, satire 讽刺作品, poignant 悲惨的 drama, historical and regional drama. To show the versatility (多面性) of the short play, I have included a guidance play, a radio play, and a television play.
Among the writers of the plays in this collection, Paul Green, Susan Glaspell, Maxwell Anderson, Thornton Wilder, William Saroyan, and Tennessee Williams have all received Pulitzer Prizes for their contributions to the theater. More information about the playwrights will be found at the end of this book.
To get the most out of reading these plays, try to picture（v. 想象，设想） the play on stage, with you, the reader, in the audience. The house lights dim (变暗). The curtains are about to （be about to do sth 正要做某事）open, and in a few minutes, the action and dialogue will tell you the story.
B
The traffic signals along Factoria Boulevard in Bellevue, Washington, generally don't flash 闪烁 the same length of green twice in a row 连续地, especially at rush hour 在上下班高峰期. At 9: 30 am, the full red/yellow/green signal cycle might be 140 seconds. By 9: 33 am, a burst of 一阵 additional traffic might push it to 145 seconds. Less traffic at 9: 37 am could push it down to 135. Just like the traffic itself, the timing时间安排 of the signals changes.
That is by design 有意安排的，计划好的. Bellevue, a fast-growing city just east of Seattle, uses a system that is gaining popularity around the US: intersection (十字路口) signals that can adjust in real time实时地 to traffic conditions. These lights, known as adaptive有适应能力的 signals, have led to significant declines in both the trouble and cost of travels between work and home.
"Adaptive signals can make sure 确保 that the traffic demand that is there is being addressed（address v. 处理）," says Alex Stevanovic, a researcher at Florida Atlantic University.
For all of Bellevue's success, adaptive signals are not a cure-all万灵药 for jammed roadways拥挤的道路. Kevin Balke, a research engineer at the Texas A&M University Transportation Institute, says that while smart lights can be particularly beneficial for（be beneficial for sth; be beneficial to sb ） some cities, others are so jammed that only a sharp reduction in the number of cars on the road will make a meaningful difference（make a difference 改善,引起变化）. "It's not going to fix everything, but adaptive signals have some benefits for smaller cities," he says.
In Bellevue, the switch to adaptive signals has been a lesson in the value of welcoming new approaches 方式,途径. In the past, there was often an automatic reaction to increased traffic: just widen the roads, says Mark Poch, the Bellevue Transportation Department's traffic engineering manager. Now he hopes that other cities will consider考虑 making their streets run smarter instead of（instead of doing sth 而不是做某事）just making（make sb/sth +adj. 使...） them bigger.
C
Challenging有挑战性的 work that requires lots of analytical分析的 thinking, planning, and other managerial管理的 skills might help（help sb/sth do sth） your brain stay sharp 保持敏锐 as you age, a study published Wednesday in the journal Neurology suggests.
Researchers from the University of Leipzig in Germany gathered聚集 more than （more than =over 超过） 1,000 retired退休的 workers who were over age 75 and assessed the volunteers' memory and thinking skills through a battery of 一系列的 tests. Then, for eight years, the scientists asked the same group to come back to the lab every 18 months to take the same sorts类型 of tests.
Those who had held mentally stimulating (刺激), demanding（demand v. 需要;强烈要求） jobs before retirement tended to do the best 做得最好 on the tests. And they tended to lose cognitive (认知) function at a much slower rate（at a +adj.+rate 以..的速度） than those with the least mentally challenging jobs. The results held true even after the scientists accounted for（account for sth 对...做出说明） the participants' overall 整体的,全面的 health status健康状态.
"This works just like physical exercise," says Francisca Then, who led the study. "After a long run 长时间, you may feel like感觉像 you're in pain在痛苦之中, you may feel tired. But it makes you fit 健康的. After a long day at work — sure, you will feel tired, but it can help your brain stay healthy保持健康.
It's not just corporate企业的 jobs or even paid work that can help keep your brain fit, Then points out. A waiter's job, for example, that requires multitasking多任务, teamwork团队合作 and decision-making做决定 could be just as stimulating as（as...as...和...一样） any high-level高水平的 office work. And "running（run v. 运营,管理） a family household requires要求,需要 high-level planning and coordinating (协调)," she says. "You have to organize the activities组织活动 of the children and take care of（take care of sth 处理，应对；take care of sb 照顾） the bills and groceries.
Of course 当然, our brains can decline as we grow older for lots of reasons — including other environmental influences环境的影响 or genetic基因的 factors. Still, continuing to challenge yourself mentally and keeping your mind（keep sb mind that ...记住） busy can only help.