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
82
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
Ourdepartmenthasalargecollectionofbooks,_____areinEnglish.
HangzhouABCExportCorporation182,XihuRoad,HangzhouSeptember15,2015Lawson&Company1470St.LouisStreetLosAngeles,
Environmentiseverythingthatsurroundsus:plants,animals,buildings,country,air,water—infacteverythingthatcanaffect
IntheUnitedStates,peoplemaygotodifferentshoppingplacesaccordingtotheireconomic【T1】______.Wealthypeopleoftengo
A、Unreasonable.B、Horrible.C、Frightening.D、Stupidandunbelievable.D男士表示“They’re(horrorfilms)sortofstupidandunbelievable
Acontractisanagreementbetweentwoormorepeopleinwhichonepersonagreestodosomethingbyaspecifieddateinreturnf
Thepresidentwhohaswontheelection______ontelevisionnextweek.
Shewantedtogoswimming,______.
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
Silvercarsaremuchlesslikelytobeinvolvedinaseriouscrashthancarsofothercolors,suggestsanewstudyofover1000
随机试题
哮喘持续状态合并混合性酸中毒时,首要处理为
某县人民法院受理一起伤害案,审判长系被害人的姐夫。一审判决后,被告人不服,提起上诉。二审人民法院认为原审法院的审判长应回避,此时应如何处理?
双液法化学堵水时,每次挤注堵剂量不超过3m3,隔离液为()。
过期妊娠是指
A.1:1B.10:1C.20:1D.50:1E.200:1非重型再生障碍性贫血,骨髓成熟红细胞与有核细胞的比值是
根据有关法律规定,招标代理服务收费方式是()
软盘携带和保管都较为方便,读写速度比较快,能存储大量数据,因此是必需的设备。()
设立管理公开募集基金的基金管理公司,其注册资本不低于()亿元人民币,且必须为实缴货币资本。
物流标准化是我国物流企业进军国际物流市场的______。
Therewas(apauseof)completestillness(which)the(buzzingof)thebeesamongthepinkrosessounded(asloudas)thefight
最新回复
(
0
)