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
2024-06-16
21
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:https://tihaiku.com/zcyy/3636817.html
相关试题推荐
[originaltext]GeneralizingabouteducationintheUnitedStatesinvolvesso
[originaltext]GeneralizingabouteducationintheUnitedStatesinvolvesso
[originaltext]GeneralizingabouteducationintheUnitedStatesinvolvesso
[originaltext]GeneralizingabouteducationintheUnitedStatesinvolvesso
[originaltext]Yourprofessorhasaskedmetotalktoyoutodayabouttheto
[originaltext]Inthe18thcenturyFrencheconomistsprotestedtheexcessive
[originaltext]Todaywearegoingtotalkaboutcopyrightingworksofart.A
[originaltext]Exportersaregoingtohavetochangeiftheyhopetopenetra
[originaltext]M:Soyou’regoingtobewritingfortheschoolnewspaper?W:Yes
[originaltext]M:Soyou’regoingtobewritingfortheschoolnewspaper?W:Yes
随机试题
[audioFiles]audio_ehbm_j14002(20082)[/audioFiles]A、Shewantedtoleavehimame
【B1】[br]【B3】[audioFiles]audio_eusm_j01_294(20099)[/audioFiles]profession根据上文a
电气火灾监控设备内部检查及吹扫时,可用抹布擦去内部电路板、电池、接线端子上的灰尘
不属于老年人患病特点的是A.常伴发多种疾病 B.应激能力差 C.疾病表现更典
作为设备工程监理工程师,应具备设备工程相关的专业背景,掌握与所从事的设备工程专业
A.3.27 B.16.69 C.21.91 D.81.75
甲公司折价购入一笔债券,将其作为可供出售金融资产核算。资产负债表日甲公司对该债券
关于双向联合体合作模式的特点,错误的是()。A:合作多以多个项目或成果为主 B
学生在学习《望庐山瀑布》这首古诗时,头脑中呈现出诗句所描绘的相关形象,这种心理活
制作固定义齿最早时间是在拔牙后A.1个月 B.2个月 C.3个月 D.3~
最新回复
(
0
)