防误闭锁装置不能随意退出运行，停用防误闭锁装置时，要经（）批准。
A、本单位生产厂长
B、本单位总工程师
C、当班值长
参考答案：B
— Why didn't you help the little boy?.
— Oh, sorry. He had struggle to his feet ______ I ran over. [ ]
A. before
B. after
C. until
D. since
短路时电压会（），将影响电气设备的正常运行。
A、逐渐下降
B、逐渐上升
C、突然下降
D、突然上升
