问题：
[单选] The projection on a shaft designed to change circular motion into up and down or back and fore motion is called （）.
wheel。crankshaft。running gear。cam。
问题：
[单选] 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.
the pump cylinder。the pump cam。the pump plunger。the pump miler。
问题：
[单选] The pumps employed on board ship can be divided into two main categories ie（） pumps and centrifugal pumps.
gear。nonpositive displacement。positive displacement。rotary。
问题：
[单选] The purpose of the flywheel of a diesel engine is to （）.
counterbalance the crank throws on the crankshaft。keep the engine running smoothly between power stroke。provide a belt-driving surface for the operation of auxiliary machinery。prevent the engine from overspeeding。
问题：
[单选] The quantity of oil injected into the cylinder can be regulated （）.
by turning the pump plunger。by vary the fuel valve spring force。by no means by controlling the governor。by enlarging or diminishing the injection hole。
问题：
[单选] The remaining oil in the lubricating pipes and ducts should be blown out with （）.
atmosphere。the fresh water。compressed air。chemical compound。
问题：
[单选] The removal of （） from lubricating oil will reduce engine wear and possible breakdowns.
contaminating water。contaminated additives。contaminated fuel。contaminating impuritie。
问题：
[单选] The rim of the piston may contain cut-out portions to accommodate （） when they open.
the gases。the air。the valves。the injector。
问题：
[单选] The rising of the exhaust temperature in manifold pipe may NOT result from （）.
too great a loading。fouled turbocharger。bad combustion。excessive air。
问题：
[单选] The scavenging air ports are located at （） that they are just exposed by the upper edge of the piston when the piston is in the bottom dead center position.
so a height。such a height。so high。such high。
