单项选择题
A.1.25kN/m3 B.0.83kN/m3 C.0.50kN/m3 D.0.20kN/m3
A.75kPa B.100kPa C.125kPa D.175kPa
A.1.55g/cm3 B.1.70g/cm3 C.1.85g/cm3 D.1.95g/cm3