矿灯灯头内有保险断电装置是防止井下瓦斯爆炸用的
参考答案：对
—Let me help you with your English, OK?
— .
A. My pleasure. B. That’s very nice of you. C. You are welcome.
6G型车钩的上翘量应不超过（）。
A、5mm
B、8mm
C、10mm
D、12mm
