搜题请搜索小程序“爱下问搜题”
问题 单项选择题

当电源电压降低时，三相异步电动机的转速（）

A.增加

B.减小

C.不变

答案

参考答案：B

选择题
— My parents like me to read some Song Dynasty poetry. What can you recommend?
— _____, but I heard Du Fu's poems are very beautiful.

A. Their thought is too extraordinary
B. There is no need to read it
C. You'd better not listen to them
D. I don't know much about it
查看答案
单项选择题

( )是指消费者在某特定时期内和一定市场上，按一定价格愿意并且能够购买的某种商品或劳务的数量。

A．供给

B．需求

C．购买能力

D．购买欲望
查看答案