My parents had to sell the old house for my further study abroad even though it was

their own wishes.

A．on

B．against

C．for

D．above

液压缸拆卸后要检查缸体内表面（）。

A.粗糙度

B.磨损量

C.相应的圆度

D.相应的圆柱度

E.直线度