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
Space is a dangerous place, not only because of meteors (流星) but also because of rays from the sun and other stars. The atmosphe
Space is a dangerous place, not only because of meteors (流星) but also because of rays from the sun and other stars. The atmosphe
admin
2010-02-20
47
问题
Space is a dangerous place, not only because of meteors (流星) 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 rem without being damaged; the figure of 60 reins has been agreed on. The trouble is that it is extremely difficult to be sure about radiation damagea person may feel perfectly well, but the cells of his or her sex organs may be damaged, and this will no be discovered until the birth of deformed children or even grandchildren.
Missions of the Apollo flights have had to cross belts of high amount of rems. 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
问题问的是为什么大气层对人类是至关重要的。文章的第四句说到了大气层屏蔽了大量的外来射线。
转载请注明原文地址:https://kaotiyun.com/show/Tyt7777K
0
大学英语四级
相关试题推荐
Heboughthiswifewhatevershewanted,___________________(不考虑花费多少).
A、Becausetheyhavenewfeaturesandfunctions.B、Becausetheyaremoresophisticatedthanothermodels.C、Becausetheyhavenew
A、Talkaboutasubjectinclass.B、Listentoaradioprogram.C、Writeanarticle.D、Readsomething.BM:Isthereanyhomeworkfo
Thepassageintroducessomekindsoftaxesandthefactorstojudgeatax.Ataxwhichiseasytocollectshouldnotinvolvea
Ifyouknowexactlywhatyouwant,thebestroutetogetajobistogetspecializedtraining.Arecentsurveyshowsthatcompan
A、50%.B、20%.C、30%.D、Allofit.CHowmuchmoneydoesMollysaveeverymonth?此题考查听特定信息即听数字的能力。解题的关键点在于抓住“Ialwaystake30%of
A、Therearen’tenoughcabinets.B、Thereistoomuchnoise.C、Officesuppliesaretakingupspace.D、Someteachingassistantsdon
Japanisanunusualmixtureoftraditionalandultra-modern.Thiscanbeconfusingforthevisitorbecause,althoughitlooksqu
A、RiceShouldbeservedwiththechicken.B、Thedisheshereareneverspicy.C、Therereallyischickeninthesalad.D、Boththe
随机试题
动脉粥样硬化最早期的病变是
A.卵巢B.肝C.输尿管D.子宫E.胆囊属于腹膜内位器官的是
患者,男,35岁,感冒后出现与体温不成比例的心动过速。应考虑是
根据《建设工程施工合同(示范文本)》,承包人提供质量保证金的方式原则上应为()。
EDI交易双方传递的文件是特定的格式,采用()报文标准。
某村本来比较落后,村支书王某想到一个创业的“点子”,希望把该村打造成3D壁画村。起初村里的老人们非常反对,认为没有什么用。但后来随着计划的实施,游客越来越多,村里的收入大为增加,老人们的态度也逐渐转变。由此可见()。①创新推动生产力的发展②认
在正三棱锥P-ABC扣,已知底面边长a=1,高h=2,则该正三棱锥的体积为().
甲为买受方,和乙签订了某房的买卖合同,其中没有违约责任约定。签订合同之后,乙见房价回升,心生后悔,便拒绝了甲提出的去房地产交易中心办理房地产登记过户手续的要求。对此,下列说法正确的是()。
我国《宪法》规定,全国人大代表在全国人大各种会议上的发言和表决不受法律追究。此项权利被称为()。
Highstreetshopsuseavarietyofmeanstoattractshoppers,suchasstrikingwindowdisplays,hugered"Sale"signsandspecia
最新回复
(
0
)