A.合金刀片損壞 B.刀尖崩刃 C.尺寸超差 D.粗糙度降低
A.數(shù)十 B.數(shù)百 C.數(shù)千 D.上萬(wàn)
A.7:24 B.1:10 C.1:20 D.莫氏6號(hào)