2013年职称英语备考每日练习理工类19

考试站网校职称英语频道首发，为了帮助学员备考2013年职称外语考试，特别整理了职称英语考试理工类:阅读理解资料，供大家复习备考之用，希望大家顺利通过考试！阅读下面的短文。每篇短文的后面有五个问题，每个问题有四个备选答案。请根据短文的内容选择最佳答案。每个试题计3分,共计15分
　　Flying the Hypert1 Skies
　　A little airplane has given new meaning to the term “going hyper．”www.examzz.com
　　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 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 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．