第3部分：概括大意与完成句子(第23～30题，每题1分，共8分)
下面的短文后有2项测试任务：(1)第23～26题要求从所给的6个选项中为第2～5段每段选择1个最佳标题;(2)第27～30题要求从所给的6个选项中为每个句子确定1个最佳选项。
LED Lighting
An accidental discovery announced recently has taken LED lighting to a new level, suggesting it could soon offer a cheaper, longer-lasting alternative to the traditional light bulb. The breakthrough adds to a growing trend that is likely to eventually make Thomas Edison’s bright invention1 obsolete. LEDs are already used in traffic lights, flashlights, and architectural lighting. They are flexible and operate less expensively than traditional lighting.
Michael Bowers, a graduate student at Vanderbilt University, was just trying to make really small quantum dots, which are crystals generally only a few nanometers big. Quantum dots contain anywhere from 100 to 1,000 electrons. They’re easily excited bundles of energy, and the smaller they are, the more excited they get. Each dot in Bower’s particular batch was exceptionally small, containing only 33 or 34 pairs of atoms.
When you shine a light on quantum dots or apply electricity to them, they react by producing their own light, normally a bright, vibrant color. But when Bowers shined a laser on his batch of dots, something unexpected happened. He was surprised when a white glow covered the table. The quantum dots were supposed to emit blue light4, but instead they were giving off a beautiful white glow.
Then Bowers and another student got the idea to stir the dots into polyurethane and coat a blue LED light bulb with the mix. The lumpy bulb wasn’t pretty, but it produced white light similar to a regular light bulb.
LEDs produce twice as much light as a regular 60 watt bulb and burn for over 50.000 hours. The Department
of Energy estimates LED lighting could reduce U. S. energy consumption for lighting by 29 percent by 2025. LEDs don’t emit heat, so they’re also more energy efficient. And they’re much harder to break.
Quantum dot mixtures could be painted on just about anything and electrically excited to produce a rainbow of colors t including white. The main light source of the future will almost surely not be a bulb. It might be a table, a wall, or even a fork.
23. Paragraph 1_____
24. Paragraph 3_____
25. Paragraph 5_____
26. Paragraph 6_____
A. LED Lighting Is Not Mature
B. LED Lighting Will Replace Traditional Lighting
C. Almost Everything Could Be the Main Light Source in the Future
D. LED Lighting Has Many Advantages
E. Bowers Made an Unexpected Discovery
F. LED Light Bulbs Look Lumpy
27. Unlike traditional lighting, LEDs do not give out heat so_____.
28. Edison’s bright invention is likely to be outdated because_____.
29. Something unexpected happened during Bower’s experiment when_____.
30. Over one quarter of energy consumption for lighting could be saved by 2025 if .
A. traditional lighting is less durable and dearer
B. a laser excited the quantum dots
C. America adopted LEDs
D. graduate students work hard
E. quantum dot mixtures are magic
F. it is more efficient
第4部分：阅读理解(第31～45题，每题3分，共45分)
下面有3篇短文，每篇短文后有5道题。请根据短文内容，为每题确定1个最佳选项。
第一篇
Eat to Live
A meager diet may give you health and long life, but it’s not much fun — and it might not even be necessary. We may be able to hang on to most of that youthful vigor even if we don’t start to diet until old age.
Stephen Spindler and his colleagues from the University of California at Riverside have found that some of an elderly mouse’s liver genes can he made to behave as they did when the mouse was young simply by limiting its food for four weeks. The genetic rejuvenation won’t reverse other damage caused by time for the mouse, but could help its liver metabolize drugs or get rid of toxins.
Spindlers team fed three mice a normal diet for their whole lives, and fed another three on half-rations. Three more mice were switched from the normal diet to half-feed for a month when they were 34 months old — equivalent to about 70 human years.
The researchers checked the activity of 11, 000 genes from the mouse livers, and found that 46 changed with age in the normally fed mice. The changes were associated with things like inflammation and free radical production — probably bad news for mouse health. In the mice that had dieted nil their lives, 27 of those 46 genes continued to behave like young genes. But the most surprising finding was that the mice that only started dieting in old age also benefited from 70 per cent of these gene changes.
“This is the first indication that these effects kick in pretty quickly.” say Huber Warner from the National Institute on Aging near Washington D. C.
No one yet knows if calorie restriction works in people as it does in mice, but Spindler is hopeful. “There’s attracting and tempting evidence out there that it will work,” he says.
If it does work in people, there might be good reasons for rejuvenating the liver. As we get older, our bodies are less efficient at metabolizing drugs, for example. A brief period of time of dieting, says Spindler, could be enough to make sure a drug is effective.
But Spindler isn’t sure the trade-off is worth it. “The mice get less disease, they live longer, but they’re hungry,” he says, “Even seeing what a diet does , it’s still hard to go to a restaurant and say: ‘I can only cat half of that’.”
Spindler hopes we soon won’t need to diet at all. His company, Lifespan Genetics in California, is looking for drugs that have the effects of caloric restriction.
31. According to the passage, which of the following is NOT true?
A. Eating less than usual might make us live longer.
B. we go on A diet when old, we may keep healthy.
C. Dieting might not be needed.
D. We have to begin dieting since childhood.
32. Why does the author mention an elderly mouse in paragraph 2?
A. To describe the influence or old age on mice.
B. To illustrate the effect of meager food on mice.
C. To tell us how mice’s liver genes behave.
D. To inform us of the process of metabolizing drugs.
33. What can he inferred about completely normally fed mice mentioned in the passage?
A. They will not experience free radical production.
B. They will experience more genetic rejuvenation in their lifetime.
C. They have more old liver genes to behave like young genes.
D. They are more likely to suffer from inflammation.
34. According to the author, which of the following most interested the researchers?
A. The mice that started dieting in old age.
B. 27 of those 46 old genes that continued to behave like young genes.
C. Calorie restriction that works in people.
D. Dieting that makes sure a drug is effective.
35. According 10 the last two paragraphs, Spindler believes that
A. calorie restriction is very important to young people.
B. seeing the effect of a diet, people will like to eat less than normal.
C. dieting is not a good method to give us health and long life.
D. drugs do not have the effects of calorie restriction.
