A.1.2g/cm3 B.1.3g/cm3 C.1.6g/cm3 D.1.8g/cm3
A.1.2g/cm3 B.1.5g/cm3 C.2.0g/cm3 D.2.5g/cm3
A.鎂土 B.鈣土 C.鈉土 D.鋁土