Now that man has actually landed on the surface of the moon, he has learned many new things about it. But one thing man knew bef

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问题     Now that man has actually landed on the surface of the moon, he has learned many new things about it. But one thing man knew before he ever reached the moon was that there was no life on it.
   There is no atmosphere (大气层) on the moon. The lack of air means that the moon is not protected from any of the sun’ s rays. The sun sends out heat and light radiation (辐射). Life on earth depends on heat and light. But the sun also sends out dangerous kinds of radiation. The earth’ s atmosphere protects us from most of them. On the moon, however, there is no atmosphere to stop the radiation. All the sun’ s rays beat down on the surface of the moon.
   Because there is no atmosphere, the moon’ s surface is either extremely hot or extremely cold. As the moon circles around the earth, the side of it that is lighted up by the sun becomes very hot. The temperature there reaches more than 300 degrees Fahrenheit (华氏温度). This is hotter than boiling water. The hot lunar day lasts two weeks. It is followed by a night that is also two weeks long. At night the temperature drops to 260 degrees below zero. This is more than twice as cold as temperatures reached at the earth’ s South Pole. Under these conditions, no form of life that we know of here on earth could exist on the moon.
Which of the following would be the best title for this text?

选项 A、Why is there no air on the moon?
B、Why is there no life on the moon?
C、Why is the moon hotter than the earth?
D、Why is the moon colder than the South Pole?

答案B

解析 主旨题。题干意为“下列哪一项是本篇文章最好的题目”。通过阅读文章,我们可知本文一开始指出月球上没有大气层,所以不能阻挡来自太阳的辐射,接着说月球上的温差变化太大,都是为了解释月球不适合人类居住的原因。所以本题的正确答案为B。
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