单项选择题
A.0.5~1 麦氏单位B.2~3麦氏单位C.4~4.5麦氏单位D.5~5.5麦氏单位
A.0.5mg/mLB.2mg /mLC.3mg /mLD.4mg/mL
A.0.1mg/mLB.2mg /mLC.3mg/mLD.4mg/mL