A.15m以遠(yuǎn) B.20m以遠(yuǎn) C.25m以遠(yuǎn) D.75m以遠(yuǎn)
A.1.50g/cm3 B.1.60g/cm3 C.1.70g/cm3 D.1.80g/cm3
A.105MPa B.70MPa C.35MPa D.21MPa