A、Exposure to even tiny amounts of radiation is fatal. B、The effect of exposure to radiation is slow in coming. C、Radiation is a

admin2009-09-12  48

问题  
Space is a dangerous place 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, ff they are inside, do prevent a lot of radiation damage. Radiation is the greatest known danger to explorers in space.  The trouble is that it is extremely difficult to be sure about radiation damage--a person may feel perfectly well, but the cells of his or her sex organs may be damaged, and this will not be discovered until the birth of deformed children or even grandchildren. Missions of the Apollo flights have had to cross belts of high radiation and, during the outward and return journey, the Apollo crew accumulated a large amount of rems, the unit of radiation. 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.

选项 A、Exposure to even tiny amounts of radiation is fatal.
B、The effect of exposure to radiation is slow in coming.
C、Radiation is avoidable in space exploration.
D、Astronauts in spacesuits needn’t worry about radiation damage.

答案B

解析 [听力原文]
What do we know about radiation in space?
由选项推测本题与辐射有关。文中关键句为“it is extremely difficult to be sure about radiation damage”,之后作者又举了例子,说明辐射给孕妇造成的影响直到畸形婴儿出生才能显现,说明这种影响是缓慢的,故正确答案为B)。其余说法均不严密。
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