A.≤0.3m/s,≤0.2m/s B.≥0.3m/s,≤0.2m/s C.≥0.3m/s,≥0.2m/s D.≤0.3m/s,≥0.2m/s
A.≤0.1 B.≤0.5 C.≤0.7 D.≤1.0
A.0.05~5 B.0.7~5 C.0.7~30 D.0.05~10