问题：
[单选] Dirt in the fuel oil system of a diesel engine can cause （）.
clogged filters。poor combustion。overloading of the diesel。shock of fuel line。
问题：
[单选] Dirty oil must be （） before being used again.
mixed with clean oil。purified。heated。strained。
问题：
[单选] Doors are generally formed in the （） of the both in-line and Vee engines to give maintenance access to the crankshaft main and connecting rod large end bearing.
bedplates。columns。cylinder blocks。safety ca。
问题：
[单选] Due to （） action of pistons some relative motion between parts in contact in the coolant supply and return system must occur.
reciprocating。rotating。running。removing。
问题：
[单选] During （）, the starting air valves should be closed to prevent the engine from turning.
overhaul。running。blowing down。All of the above are correct。
问题：
[单选] During repair,lubrication lines and orifices must be （）.
taken away。engaged。connected。sealed off。
问题：
[单选] During the inspection, the starting air valves should be closed （） the engine from turning.
to increase。to speed up。to prevent。to reduce。
问题：
[单选] During the suction stroke, the piston is moving （）.
inwards。outwards。downwards。upward。
问题：
[单选] During working, when the piston is near the （）, the air ignites the fine spray of fuel.
TDC。DTC。BDC。BCD。
问题：
[单选] Each crank is made up of two crank webs joined by a common（） to which the bottom endbearing is fitted.
throw。crankshaft。crankpin。crosshead。
