单项选择题
A.57-85Kg/m3 B.85-57Kg/m3 C.57-95Kg/m3 D.60-85Kg/m3
A.30N/cm2 B.25N/cm2 C.20N/cm2 D.35N/cm2
A.1400,4.5 B.1370,5.5 C.1370,4.5 D.1400,5.5