首页
登录
职称英语
[originaltext] Men have always wanted to fly like birds.(22)Birds can fly ea
[originaltext] Men have always wanted to fly like birds.(22)Birds can fly ea
游客
2024-02-11
38
管理
问题
Men have always wanted to fly like birds.(22)Birds can fly easily because they are light, but men’s bodies are heavier.
Men first went up into the air in balloons. These are big bags, and they are filled with gas.(23)Hydrogen is a useful gas for balloons. It is lighter than air. So balloons are usually filled with hydrogen.
Balloons have to fly with the wind, as they have no engines to drive them against it. Later, men made airships. These were balloons with engines, but they were not round.(24)They were long, and the engines were at the back. They were also filled with hydrogen and some of them caught fire, because the hydrogen escaped and the engines heated it. Then the airship was completely burnt in a few seconds. People go across the world by aircraft which have engines similar to but more powerful than those of cars. There is another kind of engine which we call the jet engine. An English engineer invented the jet engine. In May 1941 his new engine was fixed in an aircraft, and the aircraft flew quite well. Jet engines are very powerful. Usually two, three or four are enough for an aeroplane; but some big aircraft have six. Anyone in a moving jet plane can feel the power of the engines.(25)Jet planes can travel faster than sound. As a flying jet plane leaves its noise behind, we do not hear it until it has gone.
选项
A、They burn hydrogen to drive them.
B、They use engines to drive them.
C、They are full of natural gas.
D、They are filled with hydrogen.
答案
D
解析
转载请注明原文地址:https://tihaiku.com/zcyy/3440570.html
相关试题推荐
[originaltext]NewEnglandisanareaofmountains,valleys,andrivers.It
[originaltext]NewEnglandisanareaofmountains,valleys,andrivers.It
[originaltext]Throughouthistorymanhaschangedhisphysicalenvironmenti
[originaltext]Throughouthistorymanhaschangedhisphysicalenvironmenti
[originaltext]M:Ihavesomegoodnewsforyou.(19)I’vedecidedtosendyout
[originaltext]M:Ihavesomegoodnewsforyou.(19)I’vedecidedtosendyout
[originaltext]M:Ihavesomegoodnewsforyou.(19)I’vedecidedtosendyout
[originaltext]M:Couldyoudescribethetwopeoplewhorobbedthebank?W:Well
[originaltext]M:Couldyoudescribethetwopeoplewhorobbedthebank?W:Well
[originaltext]M:Couldyoudescribethetwopeoplewhorobbedthebank?W:Well
随机试题
[originaltext]I’dliketowelcomeyoualltoourActiveOutdoorClub.I’ll
Todaynanotechnology(纳米技术)isstillinaformativephase.Yetitismaturing
WilliamAppleton,authorofarecentbookentitledFathersandDaughters,be
城市居住用地一般包括以下()用地构成。A.住宅用地、公共服务设施用地、工业用地、
期货合约到期交割之前的成交价格都是()。A.相对价格 B.即期价格 C.远
下列各项中,属于城镇土地使用税的计税依据的有( )。 A.某商店由房地产管
在工程勘察实施过程中应设置报验点,必要时监理工程师对其进行()A、旁站监理 B
根据《注册建造师执业管理办法》,属于注册建造师可以同时担任两个及以上建设工程施工
某项目部承建一城市主干路工程。该道路总长30km,路面结构为:20cm石灰稳
(2019年真题)下列管材中,属于金属层状复合材料的是( )。 A.镍基合金
最新回复
(
0
)