起吊重物时，不允许绳索与吊环中心线的交角大于（）
A、30°
B、45°
C、60°
参考答案：B
-Let's go to the party this evening.
-____________________[ ]
A. When is it?
B. How are you?
C. I don't like it.
D. That's a good idea.
管道沟内连续作业时间不得超过（）小时，遇头晕、呼吸困难等情况应立即离开。
A.0.5
B.1
C.1.5
D.2
