理工类A级：阅读理解Flying the Hypert1 Skies
A little airplane has given new meaning to the term “going hyper.”
The Hyper-X2 recently broke the record for air-breathing jet planes when it traveled at a hypersonic speed 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 — 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 scramjet3.It may sound like something from a comic book，but engineers have been experimenting with scramjets since the 1960s.
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 scramjets 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 flames. However，a scramjet engine works properly only at speeds greater than five times the speed of sound.A booster rocket 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.Although the little plane’s self-powered flight lasted only 11 seconds，that brief journey on March 27 makes a major milestone on the way to a new breed of very fast airplanes，comments Werner J.A.Dahm of the University of Michigan in Ann Arbor4.In the future，engineers predict，airplanes equipped with scramjet engines could transport cargo quickly and cheaply to the brink of space. Such hypersonic jets could potentially carry passengers anywhere in the world in just a few hours.
Out of the three experimental Hyper-X aircrafts built for NASA5，only one is now left.The agency has plans for another 11-second hypersonic flight，this time at 10 times the speed of the sound.
词汇：
hypersonic/7haipE(：)5sCnik/adj.超音速的 booster/ 5bu：stE/n.助推器
equator/i5kweitE(r)/ n.赤道 milestone/5mailstEun/n.里程碑
unmanned/Qn5mAnd/adj.无人的 booster rocket 助推火箭
scramjet/5skrAmdVet/n.超音速燃烧冲压式， cargo/5kB：^Eu/n.货物 喷气发动机
combustion/kEm5bQstFEn/n.燃烧 brink/briNk/n.边缘
练习：
1. The Hyper-X broke the record because
A it was the first air-breathing jet plane.
B it flew along the equator.
C it flew at speeds smaller than five times the speed of sound.
D it traveled at a supersonic speed.
2. What kind of an engine did the Hyper-X use?
A A jet engine that gets oxygen from the air.
B A scramjet engine that doesn’t carry its own oxygen supply.
C A rocket engine that carries its own supply of oxygen.
D A iet engine that uses no oxygen.
3. What is NOT true about the scramjet engine?
A It goes slower than a rocket.
B It extracts oxygen from the air that flows through the engine.
C It works only at speeds greater than five times the speed of sound.
D It doesn’t carry its own oxygen supply.
4. What did Werner J.A.Dahm of the University of Michigan say about the Hyper-X test flight?
A It indicated the birth of a very fast airplane.
B It was self-powered，so it lasted only 11 seconds.
C It can transportcargo quickly and cheaply to the brink of space.
D It is a major milestone in the journey of making a new type of very fast airplanes，
5. What has NASA planned to do?
A To make another 11-second hypersonic flight at 10 times the speed of the sound.
B To make three more Hyper-X experiments.
C To retest the aircraft that is left.
D To make the aircraft fly higher and longer.
答案与题解：
1. C Hyper-X之所以打破纪录是因为它的飞行速度是音速的7倍。它不是第一架空气喷气式飞机，也不是第一架超音速飞机，所以A和D都不对。Hyper-X的试飞并未绕赤道飞行，所以B也是错误的选择。
2. B 第四段讲了三种发动机的氧气来源：喷气式发动机是从空气中汲取氧气，火箭发动机必须自携氧气，而超音速冲压喷气发动机则不必白携氧气，而这正是Hyper-X使用的发动机装置。
3. A 根据第五段内容，B、C、D都是正确的说法。第四段最后一句告诉我们，A的说法是不正确的。
4. D 文章的第六段中，密歇根大学的研究人员Werner J.A.Dahm说，Hyper-X的试飞成功只是研制一种新式快速飞机过程中的一个里程碑(a major milestone on the way to a new breed of very fast airplanes)，而不是新型飞机的诞生。所以，D是正确选择，A是错误选择。B也不是Werner J.A.Dahm想要表达的意思。C是其他下程师而不是Werner J.A.Dahm说的话。
5. A 答案可在最后一段找到。
