单项选择题
A.0.2h B.0.25h C.0.5h D.1.0h
A.低压 B.高压 C.常高压 D.临时高压
A.1.0~1.1m/s B.1.0~1.2m/s C.1.1~1.5m/s D.1.2~1.5m/s