单项选择题
A.the cross-head B.the pumps C.the shell D.the load
The pumps employed on board ship can be divided into tw...
单项选择题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
The pump has a constant stroke and the amount of fuel d...
单项选择题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
The projection on a shaft designed to change circular m...
单项选择题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
