问题：
[单选] Among the rings of a piston the （） one is subjected to the greatest load and temperature.
bottom。middle。top。none of the above。
问题：
[单选] An aluminum piston has lower inertia and higher coefficient of （） compared to that of cast iron.
viscosity。twisting moments。inertia。thermal expansio。
问题：
[单选] An electrically driven automatically operating auxiliary blower is provided for slow speed and （） of a low speed diesel engine.
manoeuvring operations。bad combustion。cooling。mooring trial。
问题：
[单选] An increase in load on a diesel engine results in （） of speed of the crankshaft.
a reduction。an increase。an outing。a downward。
问题：
[单选] An interlock in the remote operating valve line stops the valve （） when the engine turning gear is engaged.
to open。opening。open。opened。
问题：
[单选] An overspeed safety device is usually fitted to a generator engine for （） in the event of overspeed.
cutting power off the engine。increasing the fuel pump setting。braking the crankshaft。stabilizing the ship speed。
问题：
[单选] As a heat engine,（） energy is the source of power by which the diesel engine can be operated.
electric。heat。mechanical。exhaust。
问题：
[单选] As for a diesel engine, lack of combustion air may be due to （）.
fouling turbine。fuel pump faults。lubrication failure。excessive cooling。
问题：
[单选] As the plunger moves up, the ports are closed and the fuel （） and delivered to the injector nozzle at very high pressure.
being compressed。to be pumped up。is pressurized。are built u。
问题：
[单选] At least （） cylinders in four-stroke engine will be configured to ensure that the engine can be started with the crankshaft at whatever position.
6。2。12。8。
