问题：
[单选] Large marine diesel engines of crosshead construction generally have two systems of lubrication: a total loss system feeding the （） and a recirculation system lubricating the running gear and cooling the piston.
cylinder liners and piston rings。main bearings。crankpin bearings。turboblower。
问题：
[单选] Leaky exhaust valve will result in which of the following?（） (1) high exhaust temperature; (2) low compression pressure; (3) low firing pressure.
(1) and (2)。(1) only。(2) only。(1),(2) and (3)。
问题：
[单选] Low compression of diesel engine may result from （）
a worn cylinder。broken piston rings。any of A and B。none of the above。
问题：
[单选] Low compression results from （）.
a worn cylinder。broken piston rings。either A or B。none of the above。
问题：
[单选] Lubricating oil for an engine is stored at the bottom of the （）, known as the sump or in a drain tank located beneath the engine.
sea cheat。air receiver。crankcase。water box。
问题：
[单选] Main bearings are required to support the crankshaft at each （）.
end。web。pin。journal。
问题：
[单选] Marine four-stroke diesel engines are mainly （）.
of crosshead type。of trunk piston type。of low speed type。all the above。
问题：
[单选] Measure （） by means of lead wire.
the clearance of the main bearing。the play of the miler bearing。the gap of the main bearing。the tolerance of the main bearing。
问题：
[单选] Measure （） by means of lead wire.
the clearance of the main bearing。the diameter of main bearing。the hardness of main bearing。the tolerance of main bearing。
问题：
[单选] Modern engines （） exhaust gas driven turbo-chargers to supply pressurized fresh air for scavenging and supercharging.
are made of。are made from。make use of。are used to。
