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、When the sun is very active and explosions occur. B、When it is less than 1,500 miles away from the earth. C、When bad weather o
A、When the sun is very active and explosions occur. B、When it is less than 1,500 miles away from the earth. C、When bad weather o
admin
2018-04-15
17
问题
Not long ago it was assumed that the dangers man would meet in space would be terrible, the main ones being radiation and the danger of being hit by meteors. It is perhaps worth remembering that less than two’ centuries ago the dangers of train travel seemed similarly terrible. A man would certainly die, it was thought, if carried along at a speed of thirty kilometers per hour.
There are two sorts of radiation man must fear in space. The first is radiation from the sun, and this is particularly dangerous when the sun is very active and explosions are occurring on its surface. The second, less harmful form comes from the so-called Van Allen Belts. These are two areas of radiation about 1,500 miles away from the earth. Neither of these forms of radiation is a danger to us on the earth, since we are protected by our atmosphere. Specifically, it is that part of our atmosphere known as the ozonosphere which protects us. This is a belt of the chemical ozone between 12 and 21 miles from the ground, which absorbs all the radiation.
Once outside the atmosphere, however, man is no longer protected, and radiation can be harmful in a number of ways. A distinction must be drawn between the short- and long-term effects of radiation. The former are merely unpleasant, but just because an astronaut returning from a journey in space does not seem to have been greatly harmed, we cannot assume that he is safe. The long-term effects can be extremely serious, even leading to death.
9 What was one of the main dangers man would meet in space?
10 When is the sun radiation particularly dangerous to human beings?
11 Why did the speaker say neither of these forms of radiation is a danger to us?
选项
A、When the sun is very active and explosions occur.
B、When it is less than 1,500 miles away from the earth.
C、When bad weather occurs more frequently.
D、When there is less forest on the earth.
答案
A
解析
原文提及“太阳的辐射在太阳活跃时或在太阳表面有爆炸发生时尤其危险”。故A正确。
转载请注明原文地址:https://kaotiyun.com/show/hDT7777K
0
大学英语六级
相关试题推荐
A、Trytomakesurethatallthetest-takersarehappyinthetests.B、Designtheitemsinawaythattheytestreal-worldprofic
HowtoKeepYourNewYear’sResolutions[A]AbouthalfofallAmericanadultssaytheyareatleastsomewhatlikelytomakeaNew
Rainforestsmaystoremuchlesscarbonthanwethought.Itcouldbetimetodramaticallyreviseourestimatesfollowingthedisc
A、Raisethebikeriders’awarenessofsafety.B、ReviseallthetransportationlawsinSeoul.C、Providefreeinsuranceforthebi
Forthispart,youareallowed30minutestowriteashortessayentitledOnCollegeStudents’DrivingtoCampus.Youressaysho
SmallholderfarmersresettledtorainforestsbytheBraziliangovernmenthaveplayedanunrecognisedroleindeforestationthere
Energydrinksareastapleamongcollegestudentsandclubkids,andthey’reevenbecomingubiquitousinmanyAmerican【C1】______
A、Tohearatranslationcfhertalk.B、Tohearsignalsproducedbyelectricfish.C、Tohearsoundsusedtotrainelectricfish.
A、Consideringeasternphilosophy.B、Takingwesternmedicines.C、Changingpatients’lifestyle.D、Usingvitaminsupplements.ADr.B
随机试题
Linux操作系统的特点是
咳声如犬吠样,见于
A.桑叶B.天麻C.蒺藜D.罗布麻叶E.赭石除平肝外,能祛风通络的药是
拔火罐不适用于
在SephadexLH-20柱上,如果用甲醇-水洗脱,最先被洗脱下来的黄酮类化合物是
房地产客源的特征主要有()。
( )就是根据成本信息和施工项目的具体情况,运用一定的专门方法,对未来的成本水平及其可能发展趋势做出科学的估计,它是在工程施工以前对成本进行的估算。
合同复核人员负责根据审批意见复核合同文本及附件的完整性、准确性、合规性,内容包括()。
依照我国《(教师资格条例)实施办法》的规定,关于教师教育教学能力的标准中,不包括()。
Atfirstglancethepatriarchyappearstobethriving.Morethan90%ofpresidentsandprimeministersaremale,asarenearlya
最新回复
(
0
)