When we entered the room, the lights suddenly.
A.got off
B.set up
C.went out
D.put out
答案:C
—Turn off the TV,Jack._______ your homework now?
—Mum,just ten more minutes,please.
A.Should you be doing
B.Shouldn’t you be doing
C.Couldn’t you be doing
D.Will you be doing
定时限过电流保护的动作电流值是按线路未端短路电流整定的。()