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單項選擇題

A centrifugal pump produces the required pressure energy by means of a rotating （） provided with vanes.

A.propeller
B.impeller
C.circumference
D.screw

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單項選擇題

The pressure head of a pump is given in the unit of （）.

A.kg
B.MPa
C.meter fluid column
D.None of the above is true

單項選擇題

A gear pump belongs to （） according to its working principle.

A.reciprocating pumps
B.positive displacement pumps
C.centrifugal pumps
D.centripetal pumps