首页
登录
职称英语
[originaltext] Not long ago it was assumed that the dangers man would meet i
[originaltext] Not long ago it was assumed that the dangers man would meet i
游客
2024-04-26
8
管理
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 bell 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.
16. What was one of the main dangers man would meet in space?
17. When is the sun radiation particularly dangerous to human beings?
18. Why did the speaker say neither of these forms of radiation is a danger to us?
选项
A、They are too far away from the earth.
B、Our skin is immune to the radiation.
C、The ozonosphere protects us from it.
D、The trees can absorb the radiation.
答案
C
解析
原文提及“由于地球上的我们被臭氧层保护着,这两种辐射对我们都不造成威胁”。故C正确。
转载请注明原文地址:https://tihaiku.com/zcyy/3571735.html
相关试题推荐
[originaltext]Lastspring,SteveMcCarronhadhadenough.For10years—sinc
[originaltext]TheInternethascreatedawholenewworldofsocialcommunic
[originaltext]TheInternethascreatedawholenewworldofsocialcommunic
[originaltext]W:Goodafternoon.HowcanIhelpyou?M:Goodafternoon.Iamlo
[originaltext]M:Congratulations!Iknowyougotanewjob.Whendoyoustartt
[originaltext]M:Congratulations!Iknowyougotanewjob.Whendoyoustartt
[originaltext]M:Congratulations!Iknowyougotanewjob.Whendoyoustartt
[originaltext]M:Congratulations!Iknowyougotanewjob.Whendoyoustartt
[originaltext]M:Congratulations!Iknowyougotanewjob.Whendoyoustartt
[originaltext]M:Congratulations!Iknowyougotanewjob.Whendoyoustartt
随机试题
( )特别适合于质量小组实行质量民主管理。A.因果分析图法 B.分层法 C
在均匀分布的荷载作用面上,单位面积上的荷载值称为均布面荷载,其单位为kN/㎡。
妊娠妇女睡眠时应采取的体位是A.右侧卧位 B.左侧卧位 C.平卧位 D.半
在小腿外侧,外踝尖上8寸,胫骨前肌外缘;条口旁开1寸的穴位是A.丰隆 B.地机
61)辅助继电器可分为中间继电器、时间继电器和信号继电器。()
从所给的四个选项中,选择最合适的一个填入问号处,使之呈现一定的规律性: A.如
国外某公司从农户收购伪步行虫和蟋蟀等昆虫,把它们加工成粉末或油,再与其它食材混合
甲公司是一张3个月以后到期的银行承兑汇票所记载的收款人。甲公司和乙公司合并为
下列选项中属于建立普惠金融统计体系内容的是( )。A.扩充金融信用信息基础数据库
在进行建设工程项目总进度目标控制前,首先应该()。A.分析项目的合同结构 B.
最新回复
(
0
)