A.75,320 B.75,333.4 C.90,333.4 D.90,320
A.27,1780 B.27,1852 C.25,2000 D.26,1924
A.封閉的孔隙 B.粗大開口的孔隙 C.孔隙率大、具有微細、聯通、開口的孔隙 D.粗大封閉的孔隙