异步电动机能耗制动转矩的大小可通过调节（）来调节。
A.转子串接电阻
B.转子串接电抗
C.直流励磁电流
D.交流励磁电流
参考答案：A
—Hello! Could I speak to the headmaster?
—______, Please call back later. [ ]
A. Wait a minute
B. Hold on for a moment
C. Speaking
D. Sorry, he isn't here at the moment
A．E=，m=0
B．E=，m=
C．E=，m=0
D．E=，m=
，m=0
，m=
，m=0
，m=