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單項(xiàng)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

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單項(xiàng)選擇題

Gear pumps are of positive displacement type pumps because they discharge a near constant amount of liquid （） pressure.

A.depending on
B.in relative to
C.regardless of
D.because of

單項(xiàng)選擇題

The gear and screw pumps are classified as （）.

A.variable stroke pumps
B.multistage pumps
C.positive displacement pumps
D.triple-ported pumps