Flying the Hypert1 Skies
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.Thats about 5,000 miles per hour.At this speed,youd get around the world flying along the equator in less than 5 hours.
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 doesnt 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 aircrafts record-beating flight lasted just 11 seconds.Although the little planes 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.
词汇7haipE5sCnik 5bu:stEp
equator n.赤道 milestonen.里程碑
scramjetn.超音速燃烧冲压式, cargon.货物
combustionn.燃烧 brinkn.边缘
1. The Hyper-X broke the record because
B it flew along the equator.
D it traveled at a supersonic speed.
A A jet engine that gets oxygen from the air.
C A rocket engine that carries its own supply of oxygen.
3. What is NOT true about the scramjet engine?
B It extracts oxygen from the air that flows through the engine.
D It doesnt carry its own oxygen supply.
A It indicated the birth of a very fast airplane.
C It can transportcargo quickly and cheaply to the brink of space.
5. What has NASA planned to do?
B To make three more Hyper-X experiments.
D To make the aircraft fly higher and longer.
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。
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。
5. A 答案可在最后一段找到。
GRE数学考试常用公式大全
GRE数学词汇大全:分数和小数
GRE数学多少分算高分?
GRE数学粗心问题如何解决?
GRE考试数学词汇记忆:S类
GRE数学复习备考:12个知识点入手
GRE数学例题:数据解释题型(7)
GRE数学常见问题+备考方法介绍
GRE数学165分是不是很低?
GRE数学考试专项内容介绍
处理GRE数学专业名词有方法
常见GRE数学4大误区整理
GRE数学十例易错题集锦
GRE数学备考谨防七大误区
GRE考试数学词汇记忆:G H
GRE数学例题:数据解释题型(2)
GRE数学考点举例分析:Distributive Law
GRE数学例题:数据解释题型(4)
举例说明如何处理GRE数学读不懂题
GRE数学三大难点+解决对策
GRE数学词汇:运算词汇
GRE数学词汇大全:代数式、方程和不等式
GRE数学考试时间如何节省?
GRE数学陷阱巧躲避
GRE数学考试重要考点知识
GRE数学单位转换注意事项
合理规划GRE数学考试时间
GRE数学例题:数据解释题型(10)
GRE数学例题解析:统计学
GRE数学样题新题变化解析
不限 |
英语教案 |
英语课件 |
英语试题 |
不限 |
不限 |
上册 |
下册 |
不限 |