单选题 ( ) doesn't have any moving parts or mechanical driver but, instead, receives energy from a pressurized motive or operating fluid that creates a pumps action as it passes through the pump.

单选题 Rated head is usually marked on nameplate of a pump; however, the actual pump head may not be equal to the rated head because of ( ).

单选题 Rated head is usually marked on nameplate of a pump; however, the actual pump head may not be equal to the rated head because of ______.

单选题 Which one is not belong to the Positive Displacement Pumps ( ).

单选题 According to the theory of hydrodynamics, the mechanical energy of liquid includes ( ); and three kinds of energy can be converted into each other.

单选题 The function of pump is ( ).

单选题 If pump head is just used to lift the potential energy of liquid, and there is no flow resistance in the piping system, the pump head equals to ( ).

单选题 Which one is not belong to the Impeller Pumps (kinetic pumps) ( ).