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
专升本
Space is a dangerous place, not only because of meteors but also because of rays from the sun and other stars. The atmosphere ag
Space is a dangerous place, not only because of meteors but also because of rays from the sun and other stars. The atmosphere ag
admin
2011-04-26
18
问题
Space is a dangerous place, not only because of meteors but also because of rays from the sun and other stars. The atmosphere again acts as our protective blanket on earth. Light gets through, and this is essential for plants to make the food which we eat. Heat, too, makes our environment endurable. Various kinds of rays come through the air from outer space, but enormous quantities of radiation from the sun are screened off. As soon as men leave the atmosphere they are exposed to this radiation but their spacesuits or the walls of their spacecraft, if they are inside, do prevent a lot of radiation damage.
Radiation is the greatest known danger to explorers in space. The unit of radiation is called "rem". Scientists have reason to think that a man can put up with far more radiation than 0.1 ream without being damaged; the figure of 60 rems has been agreed on. The trouble is that it is extremely difficult to be sure about radiation damage--a person may feel perfectly well, but the cells of his or her sex organs may be damaged, and this will not be discovered until the birth of deformed (畸形的) children or even grandchildren. Missions of the Apollo flights have had to cross belts of high radiation and, during the outward and return journeys, the Apollo crew accumulated a large amount of reams. So far, no dangerous amounts of radiation have been reported, but the Apollo missions have been quite short. We simply do not know yet how men are going to get on when they spend weeks and months outside the protection of the atmosphere, working in a space laboratory. Drugs might help to decrease the damage done by radiation, but no really effective ones have been found so far.
According to the first paragraph, the atmosphere is essential to man in that ______. ( )
选项
A、it protects him against the harmful rays from space
B、it provides sufficient light for plant growth
C、it supplies the heat necessary for human survival
D、it screens off the falling meteors
答案
A
解析
转载请注明原文地址:https://kaotiyun.com/show/eGqC777K
本试题收录于:
英语题库成考专升本分类
0
英语
成考专升本
相关试题推荐
Heisat______inhisdescriptionofcountrylife.
Hewantstobecome______adoctororateacher.
Icanrememberalltheirnames,andso______myteacher.
Forthispart,youaresupposedtowriteashortessayinabout100-120wordsbasedonthefollowingsituation.描写发生在你或你的朋友身
Manypeoplefindhomegardening______.Awell-plannedandwell-keptgardencanprovideasupplyoffreshvegetables______.
Almosteveryonefailed______onthefirstday.
Cultureshockisanoccupationaldisease(职业病)forpeoplewhohavebeensuddenlytransplantedabroad.Cultureshockiscaused
Parentsshouldn’t______(favorable)oneoftheirchildrenmorethantheothers.
Thefindingsshowingeneraltermsthatcontractionofthebrainbegins______inpeopleinthecountrythaninthetowns.
Forthispart,youaresupposedtowriteashortessayinabout100-120wordsbasedonthefollowingsituation.Remembertowrit
随机试题
公共政策学的创立者是()
血培养常被污染的细菌是
A.可照常活动,但应避免体力劳动,增加午休时间B.限制活动,多卧床休息C.加强锻炼,提高耐力D.绝对卧床休息,限制探望E.逐步离床,在室内缓步行走急性心肌梗死第一周内病人应
根据《建筑法》及相关规定,施工企业应交纳的强制性保险是()。
已知2008年的元旦是星期二,问2009年的元旦是星期几?()
武夷山是雅丹地貌的杰出代表。()
Itisimportantthatthehotelreceptionist______thatguestsareregisteredcorrectly.
BetterSolarEnergySystems:MoreHeat,MoreLightSolarphotovoltaicthermalenergysystems,orPVTs,generatebothheatan
EdgarSnowwasareporterandajoumalist.Hewasadoer,aseekeroffacts.Hismatureyearswerespentincommunicatingtopeo
Musicinhighereducation:whatisitworth?[A]Musichasfounditselfincreasinglycentralinthesubjectcontroversysurround
最新回复
(
0
)