每班使用前,必须对煤电钻综合保护装置进行1次()试验。
A、合闸
B、跳闸
C、运行
参考答案:B
He ________ me to come to my birthday party, but until it was over he didn’t appear at all.
A.asked
B.told
C.agreed
D.promised
配子的运行