— I'll tell Mary about our changes tomorrow. 

— What? You ______ her yesterday. [ ]

A. ought to tell

B. must have told

C. might have told

D. should have told

线路空载冲击合闸，会产生相当高的操作过电压，故对于（）后的线路，使用这种方法来检查线路绝缘质量。

A.新投

B.检修

C.故障

D.停役