A.4個(gè) B.3個(gè) C.2個(gè) D.多個(gè)
A.30%~40% B.40%~50% C.50%~60% D.70%~80%
A.研磨;刮削 B.精車;研磨 C.精車;刮削 D.刮削;研磨