A.60~70% B.73~78% C.80~90%
A.20 B.25 C.26 D.28
A.煙煤 B.褐煤 C.腐植煤 D.無(wú)煙煤
A.100 B.200 C.250 D.300
A.8% B.16% C.12% D.20%