A.不應(yīng)大于350kg/m3 B.不應(yīng)大于550kg/m3 C.不應(yīng)大于600kg/m3 D.不應(yīng)小于600kg/m3
A.不應(yīng)大于550kg/m3 B.不應(yīng)大于320kg/m3 C.不應(yīng)大于260kg/m3 D.不應(yīng)大于300kg/m3
A.>2.5 B.>3.2 C.>2.1 D.<2.5