—I’m afraid I have to give it up.

—Remember ______ sticks to his work will succeed one day.

A．who

B．whom

C． whoever

D．no matter who

数控机床上所用的夹具主要有两类，一类用于轴类零件的夹紧，另一尖用于（）零件的夹紧。

A.盘类

B.组合类

C.箱体类

D.板类