A.粉碎 B.粉磨 C.破碎
A.机械通风 B.动力通风 C.强制通风
A.11MPA B.16MPA C.32.5MPA
A.高 B.无影响 C.低
A.2-3% B.≤2.5% C.8-12%
A.1000 B.999 C.1001
