对称负载星形联结时，负载两端的电压是电源的相电压。
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Match the following days and the names of gods in Norse Mythology. （匹配星期和北欧神话中的神）
It's high time someone ___ him to stop behaving like a child.
A. will tell
B. told
C. tell
D. should tell
My cat would not have bitten the toy fish, ___ it was made of rubber.
A. if she has known
B. she should have known
C. if she knew
D. had she known
I ____ provided you with the money. Why didn't you ask me ?
A.could have
B.had
C.must have
D.ought to have
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