单项选择题
A.1% B.2.5% C.3% D.3.5% E.5%
A.5%浅Ⅱ度 B.5%深Ⅱ度 C.10%浅Ⅱ度 D.10%深Ⅱ度 E.15%浅Ⅱ度
A.3% B.5% C.7% D.9% E.12%