You _________ sleeping on the train.[ ]
A. was
B. were
C. is
答案:B
依据《电力安全工作规程(电力线路部分)》,如需在绝缘架空地线上作业时,应用()或个人保安线将其可靠接地或采用等电位方式进行。
A.保安线
B.接地线
C.拉线
D.短路线
系统无功不足,最大的危害是()
A.频率崩溃
B.电压崩溃
C.电压降低
D.频率降低