消除镗孔后工件出现喇叭形的方法是采用（）镗孔。
A.主轴进给
B.工作台进给
C.主轴箱进给
D.平旋盘进给
参考答案：B
It is ___ the customers' needs that has made chain stores so popular in big cities in China. [ ]
A. meeting
B. met
C. to have met
D. being met
防扭钢丝绳的安全系数不小于（）。
A、2.5
B、3
C、3.5
D、4
