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问题 选择题

一个平面内有无数条直线平行于另一个平面，那么这两个平面

A．一定平行

B．一定相交

C．平行或相交

D．一定重合

答案

答案：C

平面α∥β，那么显然α内有无数条直线∥β

若α∩β=m,那么α内的所有平行于m直线都与β平行

所以这两个平面平行或相交

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Most children like watching TV. It’s very 小题1:    . By watching TV they can see and learn a lot and know many things about their country and the world. Of course, they can also 小题2:        over the radio. But they can learn better and more小题3:       on TV. Why?  Because they can hear and watch at the same time. But they can’t see 小题4:        over the radio. TV helps to open children’s小题5:         It helps to open their minds, too. They learn newer and Better ways of doing things. Many children watch TV only on Saturday or Sunday evening. But a few children watch TV every night. They go to bed very late. They can’ t have a good rest.

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变压器的铜损与变压器负载有关；（）基本恒定，与负载无关。
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