正弦交流电的瞬时值用符号（）表示。A.Um.Im.Em B.u.i.e C.U.I._爱下问搜题

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问题单项选择题

正弦交流电的瞬时值用符号（）表示。

A.Um.Im.Em

B.u.i.e

C.U.I.E

答案

参考答案：B

选择题

Quite a few tall buildings _______ the last two years.

A．have been put up

B．were put up

C．had put up

D．put up

选择题

It was sunny yesterday. But it's rainy and much ______ today.[ ]

A. cold

B. coldest

C. more colder

D. colder