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
55
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
MemoTo:AllEmployeesFrom:BerryE.Silver,PresidentDate:Oct.22,2015Subject:OurgoalsforthenextyearMarketingandS
A—costpriceF—salepriceB—factorypriceG—wholesalepriceC—netpriceH—retailpriceD—pricefreeonboardI—fixedpriceE—pur
ThereisanoldsayinginEnglish:"Laughteristhebestmedicine".Untilrecently,fewpeopletookthesayingveryseriously.N
A、Herefusedtodriveher.B、Hehasanewcar.C、Heforgothisdriver’slicense.D、Heisgladtodriveher.D由“whynot”可知Jack是欣
Whatisthepassagetalkingabout?______.
A—limitedliabilityJ—unfaircompetitionB—businessscopeK—wholesalerC—commercialchannelsL—uncollectibleaccountD—bu
A、Byplane.B、Bytrain.C、Bybus.D、Byship.A男士询问女士旅行是否愉快,女士回答说是的,这是一次顺利且愉快的飞行。由此可见,女士是乘坐飞机旅行的。
Shewantedtogoswimming,______.
Marketingbye-mailingisontheincrease.Comparedtoothermedia,e-mailmessagesareextremelycheaptosend.WithTV,youare
开幕词说明:请写一份开幕词,宣布国际交易合作讨论会开幕。内容:1.很荣幸宣布国际交易合作讨论会开幕:2.代表美国政府和人民,对讨论会表示祝贺、对来宾表示欢迎;3.相信大家的共同努力可以对国家的进一步扩大贸易带来巨
随机试题
A、 B、 C、 C问题是“报告准备好了吗”,A选项意为“是的,它已经被修理好了”,与问题明显无关;B选项意为“不,他们并没有取得很好的进步。”与问题无关,所以排除A、B选项。C选项意为“经理还得审核一下。”与题干相符,
以下属于赵树理的作品的有()
Intheyear2100,theworldisgoingtohaveapopulationofabout8billion.Mostscientistsagreethatthemostsevereproblem
我国主体功能区规划体系由()组成。
对于盈利企业,下列各项潜在普通股中,在计算稀释每股收益时,不具有稀释性的是()。
作为一名新上任的领导干部,怎样才能在同事和群众中树立威信?
S市餐饮业经营点的数量自1996年的约20000个,逐年下降至2001年的约5000个。但是,这5年来,该市餐饮业的经营资本在整个服务行业中所占的比例并没有减少。以下各项中,哪项最无助于说明上述现象?
设函数y=f(x)在区间[0,1]上非负、存在二阶导数,且f(0)=0,有一块质量均匀的平板D,其占据的区域是曲线y=f(x)与直线x=1以及x轴围成的平面图形.用表示平板D的质心的横坐标.求证:若f’(x)>0(0≤x≤1),则(如图1-10-4)
阅读以下说明,回答问题1~问题5,将解答填入答题纸对应的解答栏内。(2007年5月下午试题二)【说明】某局域网的IP地址为202.117.12.0/24,网络结构如图2.139所示。采用DHCP服务器自动分配IP地址,其中DHCPSer
Thedevelopmentofwritingwasoneofthegreathumaninventions.Itisdifficult【51】manypeopletoimaginelanguagewithoutwri
最新回复
(
0
)