A.1.25g/cm3 B.1.30g/cm3 C.1.35g/cm3 D.1.40g/cm3
A.2.5g/cm3 B.3.0g/cm3 C.2.0g/cm3 D.4.0g/cm3
A.大于 B.小于 C.等于 D.無(wú)法判斷