单项选择题
A.0.50mmB.0.40mmC.0.30mmD.0.25mm
A.3%B.4%C.5%D.6%
A.0.4B.0.5C.0.6D.0.8
A.B<9mB.9m≤B<14mC.14m≤B<18mD.B≥18m
微信扫一扫,加关注免费搜题