单项选择题
A.1.20g/cm3B.1.25g/cm3C.1.10g/cm3D.1.15g/cm3
A.2.1g/cm3B.1.8g/cm3C.1.9g/cm3D.2.0g/cm3
A.数量效率=实际精煤产率/理论精煤产率B.数量效率=理论精煤产率/实际精煤产率C.数量效率=实际精煤产率/(理论精煤产率+实际精煤产率)D.数量效率=理论精煤产率/(理论精煤产率+实际精煤产率)