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

The Hyper-X

The Hyper-X(超音速飞机)recently broke the record for air-breathing jet planes when it traveled at a hypersonic speed(超音速)of seven times the speed of sound.That’s about 5,000 miles per hour.At this speed,you’d get around the world-flying along the equator(赤道)in less than 5 hours.

The Hyper-X is an unmanned,experimental aircraft just 12 feet long.It achieves hypersonic speed using a special sort of engine known as a scramjet(超音速冲压式喷气发动机).

For an engine to burn fuel and produce energy,it needs oxygen.A jet engine,like those on passenger airplanes,gets oxygen from the air.A rocket engine typically goes faster but has to carry its own supply of oxygen.A scramjet engine goes as fast as a rocket,but it doesn’t have to carry its own oxygen supply.

A scramjet’s special design allows it to obtain oxygen from the air that flows through the engine. And it does so without letting the fast-moving air put out the combustion(燃烧)flames.However,a scramjet engine works properly only at speeds greater than five times the speed of sound.

A booster rocket(助推火箭)carried the Hyper-X to an altitude of about 100,000 feet for its test flight.The aircraft’s record-beating flight lasted just 11 seconds.“That brief journey on March 27 makes a major milestone on the way to a new breed of very fast airplanes,”says Werner J.A.Dahm of the University of Michigan in Ann Arbor.In the future,engineers predict, airplanes equipped with scramjet engines could transport cargo quickly and cheaply to the brink(边缘)of space.Such hypersonic jets could carry passengers anywhere in the world in just a few hours.

Out of the three experimental Hyper-X aircrafts built for NASA,only one is now left.The agency has plans for another 11-second hypersonic flight,this time at 10 times the speed of sound.

31.The Hyper-X broke the record because

A.it was the first air-breathing jet plane.

B.it flew along the equator.

C.it traveled at the speed of sound.

D.it reached a speed of about 5,000 miles per hour.

32.What kind of engine did the Hyper-X use?

A.A jet engine that carries its own oxygen supply.

B.A jet engine that uses no oxygen.

C.A scramjet engine that doesn’t carry its own oxygen supply.

D.A rocket engine that carries its own oxygen supply.

33.Which of the following is NOT true of the scramjet engine?

A.It has been used on passenger planes.

B.The air it breathes does not put out the combustion flames.

C.It works at speeds greater than five times the speed of sound.

D.It goes as fast as a rocket.

34.What does Werner J.A.Dahm say about the Hyper-X test flight?

A.It was unsuccessful because it lasted only 11 seconds.

B.It is a very important event in developing very fast airplanes.

C.It allows people to fly at an altitude of 100,000 feet.

D.It can transport cargo quickly and cheaply to outer space.

35.What does NASA plan to do?

A.To build one more Hyper-X aircraft.

B.To carry out three more Hyper-X experiments.

C.To make the aircraft fly higher and longer.

D.To test another hypersonic flight at 10 times the speed of sound.

第二篇

Sugar Power for Cell Phones

Using enzymes commonly found in living cells,a new type of fuel cell produces small amounts of electricity from sugar.If the technology is able to succeed in mass production,you may some day share your sweet drinks with your cell phone.

In fuel cells,chemical reactions generate electrical currents.The process usually relies on precious metals,such as platinum.In living cells,enzymes perform a similar job,breaking down sugars to obtain electrons and produce energy.

When researchers previously used enzymes in fuel cells,they had trouble keeping them active,says Shelley D.Minteer of St Louis University.Whereas biological cells continually produce fresh enzymes,there’s no mechanism in fuel cells to replace enzymes as they quickly degrade.

Minteer and Tamara Klotzbach,also of St Louis University,have now developed polymers that wrap around an enzyme and preserve it in a microscopic pocket.“We tailor these pockets to provide the ideal microenvironment for the enzyme,”Minteer says.The polymers keep the enzyme active for months instead of days.

In the new fuel cell,tiny polymer bags of enzyme are embedded in a membrane that coats one of the electrodes.When glucose from a sugary liquid gets into a pocket,the enzyme oxidizes it,releasing electrons and protons.The electrons cross the membrane and enter a wire through which they travel to the other electrode,where they react with oxygen in the atmosphere to produce water.The flow of electrons through the wire constitutes an electrical current that can generate power.

So far,the new fuel cells don’t produce much power,but the fact that they work at all is exciting,says Paul Kenis,a chemical engineer at the University of Illinois at Urhana-Champaign. “Just getting it to work,”Kenis says,“is a major accomplishment.”

Sugar-eating fuel cells could be an efficient way to make electricity.Sugar is easy to find.And the new fuel cells that run on it are biodegradable,so the technology wouldn’t hurt the environment. The scientists are now trying to use different enzymes that will get more power from sugar.They predict that popular products may be using the new technology in as little as 3 years.

36.According to the first paragraph,when can we share our sweet drinks with our cell phones?

A.When enzymes can be commonly found in living cells.

B.When the technology of producing a new type of fuel cell appears.

C.When the technology of a new type of fuel cell is suitable for mass production.

D.When the technology of mass producing cell phones appears.

37.What trouble did Minteer and Klotzhach have in their research?

A.They had trouble keeping enzymes in fuel cells active.

B.They had trouble keeping biological cells active.

C.They had trouble producing fresh enzymes.

D.They had trouble finding mechanism for producing enzymes.

38.According to Paragraph 5,electrons are released

A.when bags of enzyme are embedded in the new fuel cell.

B.when glucose from a sugary liquid goes through the enzyme.

C.when the enzyme oxidizes the glucose from a sugary liquid that goes through a pocket.

D.when the enzyme oxidizes the sugary liquid that goes through a pocket.

39.What is exciting about the new fuel cells?

A.Their limitless power generation capacity is amazing.

B.Their limited power generation capacity is a good beginning.

C.Their limited power generation capacity is the result of great efforts.

D.Their limitless power generation capacity is a major accomplishment.

40.According to the last paragraph,which is NOT true of the new fuel cells?

A.The new fuel cells run on sugar that is easy to find.

B.The new fuel cells are environment-friendly.

C.The new fuel cells are biologically degradable.

D.It will take some time before the new fuel cells can be used in popular products.

第三篇

New Material,New Fashion

The January fashion show,called Future Fashion,exemplified(例证)how far green design has come.Organized by the New York-based non-profit Earth Pledge,the show inspired many top designers to work with sustainable fabrics(纤维)for the first time.Several have since made pledges to include organic fabrics in their lines.

The designers who undertake green fashion still face many challenges.Scott Hahn, cofounder with Gregory of Rogan and Loomstate,which uses all-organic cotton,says high-quality sustainable materials can still be tough to find.“Most designers with existing labels are finding there aren’t comparable fabrics that can just replace what you’re doing and what your customers are used to,”he says.For example,organic cotton and non-organic cotton are virtually indistinguishable once woven into a dress.But some popular synthetics,like stretch nylon,still have few eco-friendly equivalents.

Those who do make the switch are finding they have more support.Last year the influential trade show Designers&Agents stopped charging its participation fee for young green entrepreneurs(企业家)who attend its two springtime shows in Los Angeles and New York and gave special recognition to designers whose collections are at least 25%sustainable.It now counts more than 50 green designers,up from fewer than a dozen two years ago.This week Wal-Mart is set to announce a major initiative aimed at helping cotton farmers go organic:it will buy transitional(过渡型的)cotton at higher prices,thus helping to expand the supply of a key sustainable material.“Mainstream is about to occur,”says Hahn.

Some analysts(分析师)are less sure.Among consumers,only 18%are even aware that ecofashion exists,up from 6%four years ago.Natalie Hormilla,a fashion writer,is an example of the unconverted consumer.When asked if she owned any sustainable clothes,she replied,“Not that I’m aware of.”Like most consumers,she finds little time to shop,and when she does,she’s on the hunt for“cute stuff that isn’t too expensive”.By her own admission,green just isn’t yet on her mind.But—thanks to the combined efforts of designers,retailers and suppliers—one day it will be.

41.What is said about Future Fashion?

A.It inspired many leading designers to start going green.

B.It showed that designers using organic fabrics would go far.

C.It served as an example of how fashion shows should be organized.

D.It convinced the public that fashionable clothes should be made durable.

42.According to Scott Hahn,one big challenge to designers who will go organic is that

A.much more time is needed to finish a dress using sustainable materials.

B.they have to create new brands for clothes made of organic materials.

C.customers have difficulty telling organic from non-organic materials.

D.quality organic replacements(替代物)for synthetics are not readily available.

43.We learn from Paragraph 3 that designers who undertake green fashion

A.can attend various trade shows free.

B.are readily recognized by the fashion world.

C.can buy organic cotton at favorable prices.

D.are gaining more and more support.

44.What is Natalie Hormilla’s attitude toward ecofashion?

A.She doesn’t seem to care about it.

B.She doesn’t think it is sustainable.

C.She is doubtful of its practical value.

D.She is very much opposed to the idea.

45.What does the author think of green fashion?

A.Green products will soon go mainstream.

B.It has a very promising future.

C.Consumers have the final say.

D.It will appeal more to young people.