相关考题
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单项选择题
A．temperatureB．speedC moistureD．time
A.temperature
B．speed
C
B.time -
未知题型
指出下列连续型随机变量分布( )。
A.二项分布
B．正态分布
C．均匀分布
D．泊松分布
E．指数分布 -
单项选择题
根据下列文章,请回答 23～30 题。 Early Ideas about the Universe 1 Early man got his ideas about the universe by looking at the stars as you do. He observed carefully, and learned many things about the sun, the moon, and the stars.2 Suppose you were asked to collect evidence about the sun as early man did. You might go out morning after morning and see it come up in the east. Even on cloudy mornings, you would observe that the darkness goes away and the world becomes light. You might not see the sun but would be sure it is there, because you notice that the earth warms up. As you continued, the sun climbs higher in the sky each day during part of the year. It stays in the sky longer. The earth gets warmer. Things begin to grow. It is spring and then summer.3 After a while the sun stays in the sky for shorter and shorter periods. Many plants begin to die. Leaves fall. Winter comes. Year after year this is repeated and you cannot tell exactly why it happens. But you realize that the sun seems to make the difference. Primitive (原始的) man felt that since the sun was so powerful it must be a god. It may seem silly to us now to worship (崇拜) a sun-god, but primitive man was right about the importance of the sun to life on earth.4 You have been told that the world is round. But suppose no one had ever taught you that the world was like a huge ball. Would you have ever thought of it yourself? You cannot see the curve (曲线) of the earth at once. You would have no idea of how big it was. That's why early man believed that the earth was small and flat. Such ideas appeared from the evidence they had.5 If you watch the stars night after night, you will see them rise and set. As you look at the sky, it is not difficult to imagine that you are in the center of a vast collection of twinkling (闪烁) lights. Some early astronomers (天文学家) believed the sky was a crystal shell or series of crystal shells, one inside the other. They believed this because that is what the night sky looked like. For many centuries, men believed that the earth was the center of the universe and that the sun, the moon, and the stars circled around it. 第 23 题 Paragraph 2________A．Early Ideas about the Sky and the StarsB．The Importance of the Sun to Life on EarthC．Primitive Knowledge of the Moon D．The Sun in Autumn and Winter E．Early Ideas about the EarthF．Collecting Evidence about the Sun
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