继电器一般有哪几种接线方式？
参考答案：
继电器一般有三相式完全星形接线、两相式不完全星形接线及两相电流差式接线三种。
-----What do you think of the girl?
------Not only _______ hard but also_____ very charming.
A．does she work ; is she
B．she works ; she is
C．does she work ; she is
D．she works ;is she
若直流串励电动机的磁路已饱和，它的转矩：（）。
A.与励磁电流平方成正比
B.与励磁电流成正比
C.与励磁电流无关
