A.5g B.10g C.15g D.20g
A.1/2~2/3 B.1/2~3/4 C.1/3~2/3 D.1/3~3/4
A.煤粉樣偏粗 B.煤粉樣偏細(xì) C.煤粉樣細(xì)度無(wú)變化