___________ you know the donut?[ ]
A. Would
B. Do
C. Are
答案:B
—When did you come back?
—Half an hour ago. You ____ to music.
A.have been listening
B.were listening
C.had listened
D.listened
防雷设施及接地装置是()。
A、将导线与杆塔绝缘
B、将导线与与大地连接
C、将电流引入大地
D、保护线路绝缘