–  Bad luck! The car breaks down again. I wish I knew about car repair.

________ you learn? Courses are offered at Seamine College.

________. I wonder when courses begin.

A．Why don’t; That’s a good idea

B．Did; That’s reasonable

C．Why don’t; I don’t care for it

D．Did; Your idea sounds very encouraging

隔离开关与断路器串联安装使用时，拉闸顺序是（）。

A.先断开刀开关后断开断路器

B.先断开断路器后断开刀开关

C.同时断开断路器和刀开关

D.无先后顺序要求