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问题 单项选择题

在计算等效三相负荷时，若既有线电压型负荷又有相电压型负荷，应先将线电压型负荷换算为( )负荷。

A．等效三相负荷

B．三相负荷

C．相电压型负荷

D．单相负荷

答案

参考答案：C

完形填空

根据对话情景和内容，从对话后所给的选项中选出能填入每一空白处的最佳选项，并在答题卡上将该选项涂黑。选项中有两个为多余选项

Acceptionist：Can I help you?

Daniel：     Yes, I’m doing some research on Roman civilization. __小题1:___

Acceptionist：These books over here are about ancient history. ___小题2:__

Daniel：     Can I check this one out?

Acceptionist：___小题3:__. It’s for reference only, so it must stay in the library. But you’re welcome to look through it.

Daniel：     Ok. ___小题4:__

Acceptionist：All right. They’re due back next Wednesday.

Daniel：     ___小题5:__

A．I’m sorry.

B．It doesn’t matter.

C．Thanks for your help.

D．They might be helpful.E. They must be useful for you.

F. And I’d like to check these books out.

G. Do you have any books on the subject?
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选择题

在苯的同系物中，加入少量酸性高锰酸钾溶液，振荡后褪色，正确的解释是

A．苯的同系物分子中，碳原子数比苯多

B．苯环受侧链影响，易被氧化

C．侧链受苯环影响，易被氧化

D．由于侧链与苯环的相互影响，使侧链和苯环均易被氧化
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