普通便携式电气测量仪表只准在瓦斯浓度（）％以下的地点使用。
A.0.5
B.1
C.1.5
D.2
参考答案：B
— I'd like to see the movie very much, but I have no money with me.
— That's OK. My _____ this time. [ ]
A. offer
B. treat
C. promise
D. service
为减轻固定处的张力，滚筒上钢丝绳应经常缠留（）圈。
A.5
B.10
C.3
