单项选择题
A.平面B.曲面C.回转表面D.沟槽
A.1#泵B.2#泵C.1#、2#、3#泵同时实现D.3#泵
A.大于B.小于C.等于D.无关
A.W=0.02491(D-S)SB.W=0.02491(D+S)SC.W=0.02491(D-S)DD.W=0.02491(D+S)D
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