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
2024-06-12
56
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 if or 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-fund rocket is, by comparison, cheap.
选项
A、The fuel is cheap.
B、They can be stopped and reignite.
C、They are cheap to build.
D、They must be used soon after fueling.
答案
C
解析
Which of the following statements is NOT the characteristic of liquid-fuel rockets?文中最后一句话“a liquid-fuel rocket is an expensive device.”故选C。
转载请注明原文地址:https://tihaiku.com/zcyy/3630605.html
相关试题推荐
[originaltext]W:Hello,listeners!Welcometoourprogram.Ourtoday’sguestis
[originaltext]W:Hello,listeners!Welcometoourprogram.Ourtoday’sguestis
[originaltext]M:Oh,Jane,you’reearly!I’mhappyyou’rehereearlytodaybeca
[originaltext]M:Oh,Jane,you’reearly!I’mhappyyou’rehereearlytodaybeca
[originaltext]BelfastistheCapitalofNorthernIslandandamajorcityin
[originaltext]Yourprofessorhasaskedmetotalktoyoutodayabouttheto
[originaltext]Inthe18thcenturyFrencheconomistsprotestedtheexcessive
[originaltext]Inthe18thcenturyFrencheconomistsprotestedtheexcessive
[originaltext]W:Wenowinterruptourregularschedulednewsprogramtobringy
[originaltext]W:Wenowinterruptourregularschedulednewsprogramtobringy
随机试题
Tomranfromthehouseinaterriblerage,hisarms______intheair.A、overridi
Manipulatedrillsthathavenorealtopichavetoremainastheyare.manipulate—
Wouldyouknowhowtohelp?Everyyear,thousandsofdriversandpasseng
Inordertolearnaforeignlanguagewell,itisnecessarytoovercomethef
横向标线的线宽最小值为50cm。()
看到“梅子”一词时,引起唾液分泌是:A.非条件反射 B.第一信号系统的活动
A.凉膈散B.普济消毒饮C.银翘散D.黄连解毒汤E.仙方活命饮有清热解毒、疏风散
某工程施工总承包单位依据施工合同约定,与甲安装单位签订了安装分包合同。基础工程完
急性肺炎患者入院16小时发生急性扁桃体炎<P>A.交叉感染<br>B.自身感染<
(2018年真题)消费基金主要用于()。A.基本建设 B.社会福利 C
最新回复
(
0
)