单项选择题
A.0.40‰ B.0.89‰ C.92.7% D.87.5% E.0.49‰
A.48.0 B.48.0-25.4=22.6 C.48.0/25.4=1.89 D.(48.0-25.4)/48.0 E.本资料不能计算