单项选择题
A.0.2-0.3mB.0.2-0.4mC.0.3-0.4mD.0.3-0.5m
A.≥70%B.≥75%C.≥80%D.≥85%
A.1~2m/hB.1~3m/hC.1~4m/hD.1~5m/h