A.選閘、試閘、擰閘 B.選閘、磨閘、擰閘 C.選閘、試閘、磨閘、擰閘 D.選閘、試閘、頓閘、擰閘
A.10~20m B.30~50m C.50~80m D.100~150m
A.制動缸 B.副風(fēng)缸 C.三通閥 D.制動管