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问题 不定项选择

如图所示，是利用传感器记录的两个物体间的作用力和反作用力的变化图线，根据图线可以得出的结论是

[ ]

A．作用力大时，反作用力小

B．作用力和反作用力的方向总是相反的

C．作用力和反作用力是作用在同一个物体上的

D．此图线一定是在两个物体都处于静止状态下显示出来的

答案

答案：B

填空题

People have always wondered about the moon. Thousands of years ago, people studied the moon and used it to keep track of time. Later, people invented instruments such as telescopes so that they could see the moon more clearly and learn about it.

With advances in technology, people were able to learn more about the moon. In the mid-1900s, scientists sent up rockets that could explore the moon’s surface. Later, astronauts actually went to the moon. They sent lots of information about the moon back to the earth. As a result of all this moon exploration, the moon is no longer as great a mystery as it once was.

Fill in the blanks according to the passage. Only one word for each blank.

根据短文内容填空（每空一分，共5分）

Long, long ago people were very 小题1:i _______ in the moon. They watched at the moon for小题2:_s______ a long time that they got to know more and more about it and they even invented a machine 小题3:_c______ a telescope. They could see the moon more clearly with it. In the middle of the 小题4:t_______ century people could set up rockets to the moon. In this way, people for the first time 小题5:__l______ on the moon and took some information back to the earth. So scientists know much more about the moon now.
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问答题 简答题

柴油在喷入燃烧室之前为什么要经过两极滤清？
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