单项选择题
A.0.2mB.0.3mC.0.4mD.0.5m
A.ΔH =1/2h+0.2B.ΔH =1/4h+0.2C.ΔH=h+0.3D.ΔH =h+0.2
A.渠道比降B.渠道糙率C.湿周D.渠道宽深比
A.A =6+2/hB.A =b+2hC.A =bhD.A =（b +mh ）h
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