"Is Bill really very ill?"    "_____. He is in hospital." [ ]

A. No, he isn't  

B. I hope so  

C. I'm afraid so  

D. I don't think so

低电压、低周减载装置动作切除的线路断路器，值班人员当系统（）及（）恢复到规定值后，应征得调度同意恢复跳闸或拉闸线路送电。

A、电压、电流

B、电压；周波

C、电压、电流

D、电流、周波