单项选择题
A.MR/MS≥1.0 B.MR/MS≥1.1 C.MR/MS≥1.2 D.MR/MS≥1.25
A.5 B.6 C.7 D.8
A.1.30~1.50 B.1.15~1.30 C.1.05~1.15 D.1.05~0.95