A.經(jīng)專(zhuān)業(yè)培訓(xùn)合格后上崗 B.人員穩(wěn)定 C.隨意更換 D.不得更換
A.光滑 B.平整 C.孔洞 D.無(wú)焊瘤
A.0.8DL B.0.86DL C.0.8DL+0.2 D.0.86DL+0.2