用测量跳动的方法检查同轴度.如同轴度0.02mm.千分表跳动量应在0.02mm以内为合格。
参考答案：对
Alibaba has become China's largest online commercial company, _____ a profit of 1.47 billion yuan in 2010. [ ]
A. earns
B. earning
C. earned
D. to have earned
刹车不灵主要表现在车床（）过程中，主轴不能迅速停止，影响工作效率，还易发生事故。
A.调试
B.加工
C.停车
D.维修
