A.懸浮—密實(shí)結(jié)構(gòu)B.骨架—空隙結(jié)構(gòu)C.骨架—密實(shí)結(jié)構(gòu)D.懸浮—骨架結(jié)構(gòu)
A.350kg/m3B.87.5kg/m3C.175kg/m3D.250kg/m3