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
2024-06-02
3
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.
(26)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-caned Van Allen Belts. There are two areas of radiation about 1 500 miles away from the earth. (28) Neither of these forms of radiation area 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.
(28) 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 (27) 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.
选项
A、Because men on the Earth are protected by the atmosphere.
B、Because radiation only have short-term effects on men on the Earth.
C、Because the Earth is quite far from the radiation areas.
D、Because the Van Allen Belts absorb all radiation.
答案
A
解析
文中提到Neither of these forms of radiation are danger to us... since we are protected by our atmosphere... Once outside the atmosphere...can be harmful in a number of ways. 地球上的人没有受到辐射伤害是因为有大气层的保护,一旦出了大气层,就会受到辐射的威胁。故正确答案为A。
转载请注明原文地址:https://tihaiku.com/zcyy/3616158.html
相关试题推荐
[originaltext]AnenvironmentalgroupcalledtheFoodCommissionisunhappy
[originaltext]AnenvironmentalgroupcalledtheFoodCommissionisunhappy
[originaltext]EveryoneknowsabouttheRoyalCanadianMountedPolice,but
[originaltext]EveryoneknowsabouttheRoyalCanadianMountedPolice,but
[originaltext]Notlongagoitwasassumedthatthedangersmanwouldmeeti
[originaltext]Notlongagoitwasassumedthatthedangersmanwouldmeeti
[originaltext]W:Exercise,exercise,exercise...wehearsomuchaboutitthese
[originaltext]W:Exercise,exercise,exercise...wehearsomuchaboutitthese
[originaltext]W:ProfessorJohnsonhelpsmesomuchthatI’mthinkingofbuying
[originaltext]W:ProfessorJohnsonhelpsmesomuchthatI’mthinkingofbuying
随机试题
November11,1918wasthedaywhentheFirstWorldWarwasover.Weary(疲劳的)v
环节一:课堂导入 出示图片,导入新课 出示图片“米歇尔访华第一天”。 活动:学生找出图片中的中国文化元素。 学生回答:四合院、书法汉字、唐装等。 教师
在非授权的情况下使用Sniffer接收和截获网络上传输的信息,这种攻击方式属于(
龙华寺是上海地区历史最悠久、规模最大的佛教古刹。( )
临床上如何判断风湿的活动性?
隔离开关电动操动机构操作电压应在额定电压的()之间。85%~110%$;$65%
外部分组按照学生的()来编班。 A.年龄B.发展水平 C.知识
共用题干 某商业和办公楼项目,高29层,钢筋混凝土结构,建筑面积45000平方
根据《环境影响评价技术导则大气环境》(HJ2.2-2018),环境空气质量现状补
患者,女性,15岁。因突发寒战,高热,呕吐入院。经检查:血压10.5/6.0kP
最新回复
(
0
)