The driver was at______loss when________word came that he was forbidden to drive for speeding. [ ]

A. a;  the  

B. /;  /

C. the;  the  

D. a;  /

一些电磁接触器，为满足吸合之初与保持吸合时对电磁吸力的不同需要，所以要设（）。

A.启动线圈

B.电阻限流机构

C.串联双绕组线圈

D.串联单绕组线圈