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
27
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://www.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
ARecentErymologyoftheWord"Culture"“文化”一词的新词源Lookinanold
[audioFiles]2013w28/audio_ezfj_013_20137[/audioFiles]Th
ThreefactorscontributetothemiraculousspreadofEnglish【C1】______an
Choosethecorrectletter,A,BorC.[br]Thehotelrestaurantspecialisesin[
图所示结构构件截面特性EA、EI相同,其中bc杆轴力的论述,下列哪一项是正确的?
某严寒地区办公建筑,采用普通机械排风系统,风机与电机采用直联方式,设计工况下的风
标准状态下将1L血液滴定至pH7.4时,所需的酸量或碱量的毫摩尔数称为A、缓冲总
影响需求变动的主要因素主要有()A.消费者的可支配收入 B.消费者
A.C位 B.C位 C.C位 D.C位 E.C位甾体母核上连接不饱和内酯
非幻觉性知觉障碍不包括( )。A.视物变形症 B.思维鸣响 C.非真实感
最新回复
(
0
)