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單項(xiàng)選擇題

It is possible to mount a double suction centrifugal pump impeller with the vanes facing in the wrong directionThis would cause the pump （）.

A.head capacity to improve
B.discharge to be reversed
C.efficiency to decrease
D.slippage to decrease

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單項(xiàng)選擇題

Water allowed to accumulate in the hydraulic system oil will cause an oxidation process producing by- products which are normally （）.

A.gums, acids, and varnishes
B.removed by cellulose type filters
C.neutralized by oil additives
D.not removed by absorbent filters

單項(xiàng)選擇題

If an anchor windlass has been idle for some time, you should （）.

A.repack all valve stems
B.lubricate it prior to use
C.replace the foundation bolts
D.balance the warping heads

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