短筒取心起钻时，禁止用转盘卸螺纹，禁止猛刹猛提，猛坐转盘。
参考答案：对
— _____ these her erasers?
— No, they _____. [ ]
A. Is, isn't
B. Are, aren't
C. Are, is
D. Is, are
发电机失磁的处理。
