单项选择题
A.1/1000~2/1000B.3/1000~4/1000C.5/1000~6/1000D.10/1000~12/1000
A.余隙调整垫片B.排气阀片C.吸气阀片D.活塞环
A.曲柄连杆机构B.螺杆C.油压平衡活塞D.滑阀