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问题 选择题

如图所示，在匀强磁场中，导体ab与光滑导轨紧密接触，ab在向右的拉力F作用下以速度V做匀速直线运动，当电阻R的阻值增大时，若速度v不变，则  

A．F的功率减小

B．F的功率增大

C．F的功率不变

D．F的大小不变

答案

答案：A

因为电阻增大，所以力F减小，F的功率P=FV，会减小，选A

改错题

短文改错：

下面短文中有10处语法错误。请在有错误的地方增加、删除或修改某个单词。

增加：在缺词处加一个漏字符号（∧）,并在其下面写上该加的词。

删除：把多余的词用斜线（\）划掉。

修改：在错的词下划一横线，并在该词下面写上修改后的词。

注意：①每处错误及其修改均仅限一词；

②只允许修改10处，多者（从11处起）不计分。

Did you enjoy yourself yesterday? I suppose you did. But I’d like to tell you how a bad day I had yesterday. Nothing just went wrong. In the morning, my alarm clock didn’t ring, so I woke up an hour late. I was in such hurry that I burnt my hand when I was cooking the breakfast. Then I ran out of the house to catch the 8:30 buses. This is the bus I usually take. But, you may laugh, I missed it of course. I am very unhappy and scared as well because teacher hates the students coming late to school. So I ran three miles to school only to discover that nobody was there. The school was quiet but peaceful. Our classroom was locking. I realized in that moment: It was Sunday.
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多项选择题

硬肿症病变脏腑为（）

A.心

B.肝

C.脾

D.肺

E.肾
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