A.0.4,0.75 B.0.5,0.8 C.0.5,0.6 D.0.6,0.75
A.0.5~1.5m/s B.0.7~1.5m/s C.0.7~2.0m/s D.0.9~2.0m/s
A.不應(yīng)小于 B.不得超過(guò) C.應(yīng)包含 D.不得超過(guò)2倍