— Oh, must you? Stay a bit longer. It has been such _____ fun having you here.

— Thanks. I've got _____ early start tomorrow morning. [ ]

A. a; an

B. /; the

C. /; an

D. the; an

当遇有电气设备着火时，应先切断电源，其拉闸顺序是（）

A、先拉操作开关，后拉闸刀开关

B、先拉隔离开关，后拉操作开关

C、不分先后