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问题 选择题

如图所示,滑动变阻器的滑片P向A端滑动,则(    )

A．电源总功率增大

B．灯泡L1变亮

C．灯泡L2变暗

D．灯泡L3变亮

答案

AB

等效电路如图.P向A端滑动时,滑动变阻器接入电路中的电阻变小,电路总电阻R减小,即L1､L2变亮,L3变暗,总功率变大,故A､B正确.

改错题
短文改错。
     此题要求改正所给短文中的错误。对标有题号的每一行作出判断：
     如有错误（每行只有一个错误），则按下列情况改正：
     此行多一词：把多余的词用斜线（\）划掉，在该行右边横线上写出该词，并也用斜线（\）划掉。
     此行缺一个词：在缺词处加一个漏字符号（∧）,在该行右边横线上写出该加的词。
     此行错一个词：在错的词下划一横线，在该行右边横线上写出改正后的词
     注意：原行没有错的不要改。
May 10,2007                                           Fine
     Today I was having a PE lesson while I fell down
and hurt my foot. I was in greatly pain at that moment, 
but I tried to act as if nothing has happened until the
class was over. Though I had difficulty walk back to 
my classroom, I still didn't tell anyone but even refused
the offer of help of my classmates. As result, the hurt
in his foot became worse. Now I know I'm wrong. We 
can tell others our need for help and accept his help.
Some day we can not help others in return. In this way,
we can get along to each other happily and peacefully.
1._____
2._____
3._____
4._____
5._____
6._____                   
7._____
8._____
9._____
10._____
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单项选择题

信箱和______为32位应用程序提供了在Windows密封内存情况下彼此通信的方法。 ( )

A．管道

B．线程

C．CDC

D．VDD
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