單項(xiàng)選擇題

The pumps employed on board ship can be divided into two main categories ie（） pumps and centrifugal pumps.

A.gear
B.nonpositive displacement
C.positive displacement
D.rotary

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單項(xiàng)選擇題

The pump has a constant stroke and the amount of fuel delivered is regulated by rotating （） which has a specially arranged helical groove cut into it.

A.the pump cylinder
B.the pump cam
C.the pump plunger
D.the pump miler

單項(xiàng)選擇題

The projection on a shaft designed to change circular motion into up and down or back and fore motion is called （）.

A.wheel
B.crankshaft
C.running gear
D.cam

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