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
17
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
Fertilizerusehasexploded,overloadingplantsworldwide,likelyalteringe
Someconsumerresearchersdistinguish【C1】______"rational"motivesand"emot
Attheendofthevacation,thesestudents________(praise)forbeingoutstandin
患儿男,3岁。出生以来发现尿道口位置异常。查体:尿道外口位于阴茎中部,阴茎向腹侧
某运输企业投资一项目,预计6年后可获利800万元。按年利率12%计算,这笔收益的
Fordecades,farmersandenvironmentalist
患儿,男性,6岁,因舌部血管瘤拟在全身麻醉下手术切除,采用气管内插管全身麻醉的最
下列各项中,不属于会计监督的主要内容的是()。A.对原始凭证进行审核和监督
混凝土拌合物的和易性是一项综合性技术性能,包括( )。A.流动性 B.黏聚性
关于施工图预算与施工预算区别的说法,正确的是( )。A.施工图预算的编制以施工
最新回复
(
0
)