首页
登录
职称英语
[originaltext] The great advance in rocket theory 40 years ago showed that l
[originaltext] The great advance in rocket theory 40 years ago showed that l
游客
2023-09-17
52
管理
问题
The great advance in rocket theory 40 years ago showed that liquid-fuel rockets were far superior in every respect to the skyrocket with its weak solid fuel, the only kind of rocket then known. However, during the last decade, large solid-fuel rockets with solid fuels about as powerful as liquid fuels have made their appearance, and it is a favorite layman’s question to inquire which one is "better". The question is meaningless; one might as well as ask whether a gasoline or a diesel engine is "better". It all depends on the purpose. A liquid-fuel rocket is complicated, but has the advantage that it can be controlled beautifully. The burning of the rocket engine can be stopped completely; it can be reignited when desired. A solid-fuel rocket, on the other hand, is rather simple in construction, though hard to build when a really large size is desired. But once you have a solid-fuel rocket, it is ready for action at a very short notice. A liquid-fuel rocket has to be fueled first and can not be held in readiness for very long after it has been fueled. However, once a solid-fuel rocket has been ignited, it will keep burning. It can’t be stopped and reignited whenever desired. Because a solid-fuel rocket can be kept ready for a long time, most military missiles employ solid fuels, but manned space flight needs the fine adjustments that can only be provided by liquid-fuel rocket. It may be added that a liquid-fuel rocket is an expensive device; a large solid-fuel rocket is, by comparison, cheap.
选项
A、Neither of the two types of rockets is very economical.
B、The liquid-fuel rocket is best.
C、Each type of rocket has certain advantages.
D、The solid-fuel rocket is best.
答案
C
解析
What conclusion can we draw from the passage?
转载请注明原文地址:http://tihaiku.com/zcyy/3020551.html
相关试题推荐
[originaltext]WhenJohnMilton,writerofParadiseLost,enteredCambridge
[originaltext]WhenJohnMilton,writerofParadiseLost,enteredCambridge
[originaltext]M:We’llcontinuewiththeworkofinvestigation.Laura,anident
[originaltext]M:We’llcontinuewiththeworkofinvestigation.Laura,anident
[originaltext]M:We’llcontinuewiththeworkofinvestigation.Laura,anident
[originaltext]W:Ithinkifyouwanttogetsomeexcitementinyourlifeyouou
[originaltext]W:Ithinkifyouwanttogetsomeexcitementinyourlifeyouou
[originaltext]W:Ithinkifyouwanttogetsomeexcitementinyourlifeyouou
[originaltext]W:OurPresident,sinceleavingofficefiveyearsago,hasspent
[originaltext]Investmentinthepublicsector,suchaselectricity,irrigat
随机试题
Perhapsmorethananythingelse,scientistsareeagertofindoutifMartian
Therewillbea(n)______telecastoffootballmatchtonight.A、livelyB、activeC、
Whendidthespeakerlearntosmoke?Thespeakerlearnstosmokeat______.[br
____ofthemwasgodenoughtouse.( )A
某患者骨髓非红系(NEC)分类:原始单核细胞11%,幼稚单核细胞70%,其他细胞
根据系统不响应安全联锁要求的概率将安全仪表系统(SIS)分为1级、2级、3级3个
治疗虚寒崩漏下血,应选用的药物是()A.白茅根 B.大蓟 C.白及
我国基金从业人员职业道德规范的内容不包括()A.大客户利益优先 B.专业审慎
事物度的原理,要求我们要注意“适度”的原则,根据情况决定能不能超越和破坏事物的度
对于保证收益理财计划,风险提示的内容应包括的语句是()。A.本理财计划有投资风
最新回复
(
0
)