Nuclear Power and Its Danger Nuclear power’s danger to health, safety, and even life itself can be summed up in one word;rad

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问题                         Nuclear Power and Its Danger
    Nuclear power’s danger to health, safety, and even life itself can be summed up in one word;radiation.
    Nuclear radiation has a certain mystery about it, partly because it cannot be detected by human senses. It can’ t be seen or heard, or touched, or tasted, even though it may be all around us. There are other things like that. For example, radio waves are all around us but we can’t detect them, sense them, without a radio receiver. Similarly, we can’ t sense radioactivity without a radiation detector. But unlike common radio waves, nuclear radiation is not harmless to human beings and other living things.
    At very high levels, radiation can kill an animal or human being outright by killing masses of cells in vital organs. But even the lowest level of radiation can do serious damage. There is no level of radiation that is completely safe. If the radiation does not hit anything important, the damage may not be significant. This is the case when only a few cells are hit, and if they are killed outright. Your body will replace the dead cells with healthy ones. But if the few cells are only damaged, and if they reproduce themselves, you may be in trouble. They reproduce themselves in a deformed way. They can grow into cancer. Sometimes this does not show up for many years.
    This is another reason for some of the mystery about nuclear radiation. Serious damage can be done without the victim being aware at the time that damage has occurred. A person can be irradiated and feel fine, then die of cancer five, ten, or twenty years later as a result. Or a child can be born weak or liable to serious illness as result of radiation absorbed by its grandparents. Radiation can hurt us. We must know the truth.
Radiation can cause serious consequences even at the lowest level______.

选项 A、when it kills few cells
B、if it damages few cells
C、though the damaged cells can repair themselves
D、unless the damaged cells can reproduce themselves

答案B

解析 由文章第三段第一句和第二句“At very high levels,radiation can kill an animal or humanbeing outright by killing masses of cells in vital organs.But even the lowest level of radiation can doserious damage.”可知,高强度的核辐射通过杀死主要器官里的大量细胞,导致动物或人类立刻死亡。不过即使是最低强度的辐射也可能造成严重的后果(通过损伤主要器官里的少量细胞)。由第二句中的but可知,这是两个对比句,后面一句省略了“by killing little cells in vital organs”。故选B。
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