第4部分:阅读理解(第31~45题,每题3分,共45分)

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

Weaving with Light

In the Sierra Madre mountain range of west central Mexico,the native Huichol people live much the way their ancestors did—without electricity.That’s because it’s too expensive to string power lines to the remote mountain areas where they live.To help support themselves,the Huichol create beautiful artwork.They sell their art in cities hundreds of miles away from their villages. And without electricity—at home or on the road,they can only work during daylight hours.When it gets dark,they must stop whatever they’re doing.

Now,a team of scientists,designers,and architects is using new technologies to provide the Huichol with light after the sun sets.The scientists’technique involves weaving tiny electronic crystals into fabrics that can be made into clothes,bags,or other items.

By collecting the sun’s energy during the day,these lightweight fabrics provide bright white light at night.Their inventors have named the fabrics“Portable(轻便的)Lights”.Portable Lights have the potential to transform the lives of people without electricity around the world.

At the core of Portable Lights technology are devices called high-brightness light-emitting diodes(高亮度发光二极管),or HB LEDs.These tiny lights appear in digital clocks,televisions, and streetlights.

LEDs are completely different from the light bulbs(灯泡).Most of those glass bulbs belong to a type called incandescent lights(白炽灯).Inside,electricity heats a metal coil(线圈)to about 2,200 degrees Celsius.At that temperature,bulbs give off light we can see.Ninety percent of energy produced by incandescent lights,however,is heat—and invisible.With all that wasted energy,bulbs burn out quickly.They are also easily broken.

LEDs,on the other hand,are like tiny pieces of rock made up of molecules(分子)that are arranged in a crystal structure.When an electric current passes through a LED,the crystal structure produces light.Unlike incandescent bulbs,they can produce light of various colors.Within a LED, the type of molecules and their particular arrangement determine what color is produced.

31.The Huichol don’t use electricity because

A.it is too difficult for them to change their lifestyle.

B.they know nothing about it.

C.it costs too much to string power lines.

D.they don’t need it.

32.To make a living,the Huichol create artwork and

A.sell it to tourists in their villages.

B.sell it in cities far away from their villages.

C.display it in their village museums.

D.keep it in their homes to attract tourists.

33.The central part of the Portable Lights technology is

A.glass bulbs.

B.digital clocks.

C.incandescent lights.

D.HB LEDs.

34.All of the following are disadvantages of incandescent lights EXCEPT that

A.they are not bright enough.

B.they burn out quickly.

C.they are easily broken.

D.they waste most of the energy produced.

35.LEDs are different from light bulbs in that

A.LEDs are made up of tiny pieces of rock.

B.LEDs can send out light of different colors.

C.LEDs belong to incandescent lights.

D.LEDs look like crystals.

第二篇

The Differences in Living Standards

The differences in living standards around the world are vast.In 1993,the average American had an income of about$25,000.In the same year,the average Mexican earned$7,000,and the average Nigerian earned$l,500.Not surprisingly,this large variation in average income is reflected in various measures of the quality of life.Changes in living standards over time are also large.In the United States,incomes have historically grown about 2 percent per year(after adjusting for changes in the cost of living).At this rate,average income doubles every 35 years.In some countries,economic growth has been even more rapid.In Japan,for instance,average income has doubled in the past 20 years,and in South Korea it has doubled in the past 10 years.

What explains these large differences in living standards among countries and over time?The answer is surprisingly simple.Almost all variation in living standards is attributable to differences in countries’productivity—that is,the amount of goods and services produced from each hour of a worker’s time.In nations where workers can produce a large quantity of goods and services per unit of time,most people enjoy a high standard of living;in nations where workers are less productive,most people must endure a more meagerexistence.Similarly,the growth rate of a nation’s productivity determines the growth rate of its average income.

The fundamental relationship between productivity and living standards is simple,but its implications are far-reaching.If productivity is the primary determinant of living standards,other explanations must be of secondary importance.For example,people might think that labor unions or minimum-wage laws contributed to the rise in living standards of American workers over the past century.Yet the real hero of American workers is their rising productivity.

The relationship between productivity and living standards also has great implications for public policy.When thinking about how any policy will affect living standards,the key question is how it will affect our ability to produce goods and services.To improve living standards,policy makers need to raise productivity by ensuring that workers are well educated,have the tools needed to produce goods and services,and have access to the best available technology.

36.Which of the following countries has enjoyed the fastest economic growth in history?

A.Mexico. B.The United States.

C.Japan. D.South Korea.

37.The word“meager”in the second paragraph is closest in meaning to

A.modest. B.poor. C.meaningless. D.plentiful.

38.What is the most important factor that leads to the rise in living standards of average people?

A.Labor unions. B.Minimum-wage laws.

C.Rising productivity. D.Favorable public policy.

39.The study of the relationship between productivity and living standards is significant in that

A.it calls policy makers’attention to a qualified work force.

B.it encourages workers to get better education.

C.it helps improve the workers’ability to produce goods and services.

D.it enables policy makers to access the latest technology.

40.The passage mainly discusses

A.the differences in average income among countries.

B.the relationship between productivity and living standards.

C.the causes of the rise in living standards.

D.the importance of raising productivity.

第三篇

Making Light of Sleep

All we have a clock located inside our brains.Similar to your bedside alarm clock,your internal clock runs on a 24-hour cycle.This cycle,called a circadian rhythm,helps control when you wake, when you eat and when you sleep.

Somewhere around puberty,something happens in the timing of the biological clock.The clock pushes forward,so adolescents and teenagers are unable to fall asleep as early as they used to.When your mother tells you it’s time for bed,your body may be pushing you to stay up for several hours more. And the light coming from your computer screen or TV could be pushing you to stay up even later.

This shift is natural for teenagers.But staying up very late and sleeping late can get your body’s clock out of sync with the cycle of light and dark.It can also make it hard to get out of bed in the morning and may bring other problems,too.Teenagers are put in a kind of a gray cloud when they don’t get enough sleep,says Mary Carskadon,a sleep researcher at Brown University.It affects their mood and their ability to think and learn.

But just like your alarm clock,your internal clock can be reset.In fact,it automatically resets itself every day.How?By using the light it gets through your eyes.Scientists have known for a long time that the light of day and the dark of night play important roles in setting our internal clocks.For years, researchers thought that the signals that synchronize the body’s clock were handled through the same pathways that we use to see.

But recent discoveries show that the human eye has two separate light-sensing systems.One system allows us to see.The second system tells our body whether it’s day or night.

41.The clock located inside our brains is similar to our bedside alarm clock because

A.it controls when we wake,when we eat and when we sleep.

B.it has a cycle of 24 hours.

C.it is a cycle also called circadian rhythm.

D.it can alarm any time during 24 hours.

42.What is implied in the second paragraph?

A.Young children’s biological clock has the same rhythm with that of the teenagers.

B.People after puberty begin to go to bed earlier due to the change of the biological clock.

C.Children before puberty tend to fall asleep earlier at night than adolescents.

D.Teenagers go to bed later than they used to due to the light from the computer screen.

43.In the third paragraph the author wants to tell the readers that

A.it is natural for teenagers to stay up late and get up late.

B.staying up late has a bad effect on teenagers’ability to think and learn.

C.during puberty most teenagers experience a kind of gray cloud.

D.it is hard for teenagers to get out of bed in the morning.

44.Which of the following statements is NOT true according to the fourth and fifth paragraphs?

A.Our biological clock resets itself automatically.

B.Light gets through our eyes and resets our biological clock.

C.Our internal clock as well as the alarm clock can be reset automatically.

D.Our internal clock,like the alarm clock,can be reset.

45.According to the last two paragraphs,what did the previous researchers think about the human eye’s light-sensing system?

A.The human eye had two light-sensing systems.

B.The human eye had one light-sensing system.

C.The human eye could sense the light of day more quickly than the dark of night.

D.The human eye could reset our internal clocks in accordance with the alarm clocks.