磨削外圆时,若砂轮不平衡,砂轮硬度过高,砂轮钝化,则工件表面会出现()振痕。
参考答案:直波形
–When has the country been united as one?
--______1998, I suppose.
A.In
B.From
C.After
D.Since
碘酊用于口腔内消毒剂的浓度是
A.2.5%
B.2.0%
C.1.5%
D.1%
E.0.5%