单项选择题
A.30.2m2 B.620.6m2 C.62.06m2 D.302.07m2
A.30%~50% B.30%~40% C.20%~30% D.40%~50%
A.①→②→③→④ B.④→②→③→① C.④→③→②→① D.②→③→④→①