A.先用砂紙粗磨、細磨、再拋光 B.先用砂紙細磨、粗磨、再拋光 C.先用拋光、再用砂紙粗磨、細磨
A.GB/T232 B.GB/T231 C.GB/T228
A.GB/T228 B.GB/T231 C.GB/T232