气焊焊补灰口铸铁的冷却速度要比手工电弧焊（）得多。
A.快
B.慢
C.差不
参考答案：B
My sister_____ Tony for ten years next year.
A．has been married to
B．has married to
C．will be married to
D．will marry to
检维修作业时为什么必须切断动力源并进行锁定，设立安全标识牌，同时指定监护人？
