首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
A、Its chemical elements must be studied. B、Its temperature must be lowered. C、Big spaceships must be built. D、Its atmosphere mus
A、Its chemical elements must be studied. B、Its temperature must be lowered. C、Big spaceships must be built. D、Its atmosphere mus
admin
2009-04-23
45
问题
Science fiction writers have often imagined human beings going to live on Mars. But these days, scientists are taking the idea seriously. It has a great deal to recommend it, since it might solve the problem of overcrowding on the earth. But obviously, it would not be worth making the effort unless people could live there naturally. If the atmosphere were like that of the earth, this might be possible. But in fact it is mostly carbon dioxide. Apart from that, there are other problems to be overcome. For example, the temperature would have to be raised from 60 degrees below zero to 15 degrees above it. Scientists who study Mars have laid down the program that they can follow. To begin with, they will have to find out whether life has ever existed on the planet of Mars in the past. Secondly, they will have to make a reliable map of its surface. And finally, they will have to make a list of the gases. Above all, they will have to discover how much nitrogen it possesses, since nitrogen is four fifths of the air we breathe. They are surprisingly optimistic about raising the temperature on Mars and believe it could be done in two hundred years. It will take a bit longer, though, to transform the atmosphere so that human beings, could live there. Scientists estimate that this will take one hundred thousand years.
选项
A、Its chemical elements must be studied.
B、Its temperature must be lowered.
C、Big spaceships must be built.
D、Its atmosphere must be changed.
答案
D
解析
What is one of the things that must be done before man can live on Mars?
转载请注明原文地址:https://kaotiyun.com/show/SFZK777K
0
大学英语六级
相关试题推荐
Gmail(GoogleEmail)NoticeSubject:YourGmailaccounthasbeeninactiveforalongtimeFrom"TheGmailTeam"gmail-noreply@gm
Theguestpaid(little)______moneythanheshouldfortheroom.
Icouldhavecalledyouyesterday,butI_____yourtelephonenumber.
A、Byship.B、Bytrain.C、Byplane.D、Bybus.C题目询问的是查尔斯将怎么去澳大利亚度假。由对话中女士的问话“你打算怎么去那里”及男士的回答“当然是坐飞机”,可以得出正确答案为C项(坐飞机)。
A、Fromthebankheisworkingfor.B、Fromhisfriends.C、Fromanotherbank.D、Fromhisoffice.C根据文中男士的回答“I’llborrowsomemoney
ManyChinesestudentswantto【T1】______theirMaster’sorPh.D.’sdegreeinforeignuniversities,especiallyinAmericanscho
ManyChinesestudentswantto【T1】______theirMaster’sorPh.D.’sdegreeinforeignuniversities,especiallyinAmericanscho
Bytheendofthisyear,he______inthisfactoryforasmanyasthirtyyears.
Thesuccessfulcompletionofthebookistheresultofthecooperationandconfidenceofmanypeople.
A、At11’clock.B、At4o’clock.C、At7o’clock.D、At2o’clock.CM:MissGreen,ItoldDr.SmiththatIwouldcallhiminthePa
随机试题
A.厌食B.消谷善饥C.饥不欲食D.偏食异物胃中有虫可见
患者,男性,27岁,高空坠落致脊柱骨折伴脊髓损伤,查体示:双上肢呈屈曲状态,可完成屈肘和腕背伸动作,不能伸肘,双侧中指以下感觉丧失,其损伤平面为
可行性研究的主要作用是为建设项目( )提供依据。
在决定购买工程保险时,要选择保险公司,确定恰当的保险范围,免赔额、保险费,这些是( )的重要内容。
A企业2×11年1月1日发行的2年期公司债券,实际收到款项193069元,债券面值200000元,每半年付息一次,到期还本,票面利率10%,实际利率12%。采用实际利率法摊销溢折价,计算2×11年12月31日应付债券的账面余额是()。(计算结果保留
下面谱例的旋律片段体现了20世纪哪种音乐创作风格?()
研究人员对四川地区出生的一批恐龙骨骼化石进行分析后发现,骨骼化石内的砷、钡、铬、铀、稀土元素等含量超高,与现代陆生动物相比,其体内的有毒元素要高出几百甚至上千倍。于是一些古生物学家推测这些恐龙死于慢性中毒:如果以下各项为真,不能质疑上述推测的是:
喜克索斯人
A、操作简易,价格便宜B、可进行思维、学习、记忆等工作C、有几个柜子那么大D、小型化、微型化、低功耗等D录音中提到“其一大特点就是五个吉祥物的头饰部分”,所以选D。
Scholarsoftheinformationsocietyaredividedoverwhethersocialinequalitydecreasesorincreasesinaninformation-basedso
最新回复
(
0
)