螺口灯座的螺口应与（）连接。
A.工作零线
B.中性线
C.保护底线
D.相线
参考答案：A
—I think math is more useful than Chinese.
—I don't _____ you. They are both useful. [ ]
A. catch up with
B. get on well with
C. talk with
D. agree with
中速磨煤机内部着火现象有哪些，如何处理？
