首页
登录
职称英语
Space is a dangerous place, not only because of meteors (流星) but also becaus
Space is a dangerous place, not only because of meteors (流星) but also becaus
游客
2024-03-02
42
管理
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. [br] The harm radiation has done to the Apollo crew members ______.
选项
A、is significant
B、seems overestimated
C、is enormous
D、remains unknown
答案
D
解析
从文章中我们得知,到现在为止还没有报告显示阿波罗号受到辐射损害,所以A,B, C选项均与文章意思相悖,只有D相对正确。
转载请注明原文地址:https://tihaiku.com/zcyy/3499343.html
相关试题推荐
Spaceisadangerousplace,notonlybecauseofmeteors(流星)butalsobecauseofr
[audioFiles]audio_eufm_j01_211(200910)[/audioFiles]A、Becauseshewassick.B、Be
Americansenjoyfastfoodmainlybecause______.[br]Theexpression"pitchin
Americansenjoyfastfoodmainlybecause______.[br]Accordingtothetext,a
PaulineGrossfeltsearedbecauseshethoughtshewoulddieof______.[br]From
PaulineGrossfeltsearedbecauseshethoughtshewoulddieof______.[br]InA
PaulineGrossfeltsearedbecauseshethoughtshewoulddieof______.[br]Coup
PaulineGrossfeltsearedbecauseshethoughtshewoulddieof______.[br]What
PaulineGrossfeltsearedbecauseshethoughtshewoulddieof______.[br]The
PaulineGrossfeltsearedbecauseshethoughtshewoulddieof______.[br]Gene
随机试题
Whatisthetopicofthetalk?[br][originaltext]AlthoughIthinktheUnit
[originaltext]M:Susan,doyouknowwhenProfessorJones’BiologyFinalis?W:
Manypeoplespendalotoftimeonthewaytotheoffice,butthereisagrowing
仓库按结构形式分为()。A.仓储式 B.露天式 C.封闭式 D
健康档案管理的基本原则是()A.体现健康管理和连续服务的特点 B.社区工作
乌药的功效是A.行气止痛,温肾散寒 B.行气止痛,杀虫,解毒消肿 C.行
(2019年真题)我国城镇固定资产投资2016年为596500.8亿元,2017
某公司净经营资产净利率20%,平均利息率8%,净财务杠杆40%,企业所得税率25
与债务筹资相比,股权筹资的优点有( )。A.股权筹资是企业稳定的资本基础 B
某工程施工过程中发生如下事件:①因异常惡劣候条件导致工程停工2天,人员窝工20个
最新回复
(
0
)