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
2024-05-01
4
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 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 he 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、Traffic accidents.
B、Radiation.
C、Train travel.
D、Air crash.
答案
B
解析
原文提及“不久前人们认为在太空中会遭遇到严重的威胁,主要有辐射和流星撞击”。故B正确。
转载请注明原文地址:https://tihaiku.com/zcyy/3579820.html
相关试题推荐
[originaltext]M:Howareyournewneighbors?W:Theyseemniceenough,butthey
[originaltext]M:Howareyournewneighbors?W:Theyseemniceenough,butthey
[originaltext]W:Goodafternoon.CanIhelpyou?M:Yesplease.I’mlookingfor
[originaltext]W:Goodafternoon.CanIhelpyou?M:Yesplease.I’mlookingfor
[originaltext]W:MaybeweshouldtakeFrontStreetthismorning.Theradioanno
[originaltext]W:MaybeweshouldtakeFrontStreetthismorning.Theradioanno
[originaltext]W:MaybeweshouldtakeFrontStreetthismorning.Theradioanno
[originaltext]W:MaybeweshouldtakeFrontStreetthismorning.Theradioanno
[originaltext]W:MaybeweshouldtakeFrontStreetthismorning.Theradioanno
[originaltext]W:MaybeweshouldtakeFrontStreetthismorning.Theradioanno
随机试题
Whatispopculture?Well,popis【11】forpopular.Thebeginningofpopcultu
根据有关法律规定,下列机构中一般不得作为贷款保证人的有()。A.公立医院
45岁女性患者因头痛头晕加重半天看急诊,自述近3年来明显发胖,近半年来口渴,乏力
生物医学模式向生物一心理一社会医学模式的转变,引起了医德的一系列变化,但应除外A
某测绘单位承担了某县地理国情普查项目,需要生产该县0.5m分辨率数字正射影像图(
阅读下面的材料,根据要求写作文。 教育学家陶行知说过:处处是想象创造之地,天天
人是自然性与社会性的统一体,个体的早期发展更多地体现了()。 A.自然属性
关于运动性言语中枢,下列说法正确的包括()。A、又称为布洛卡中枢B、主要负责“
基础心理学是研究()。 (A)正常成人心理现象的心理学基础学科 (B
女,19岁,上前牙松动3年,检查见上切牙松动Ⅱ°,扇形移位,口腔卫生较好,初步印
最新回复
(
0
)