单项选择题
A.60%~65% B.60%~70% C.65%~75% D.70%~80%
A.65.4 B.54.5 C.76.3 D.81.8
A.0.1~1kg/m3 B.0.15~1.5kg/m3 C.0.2~2kg/m3 D.0.25~2.5kg/m3