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单选题
Crankshafts of medium speed engines are （） from a single piece of steel.
A
unusually solid welded
B
never be solid forged
C
almost invariably solid forged
D
almost invariably be welded
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is usually cooled by sea waterB
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is in direct contact with the water in the bore of the cylinderD
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单选题The crankshafts of medium speed engines are almost invariably solid （） from a single piece of steel.A
forgedB
castC
madeD
shrunk
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the piston rodsB
the crank throwsC
the thrust bearingsD
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考题
单选题What best describes processing delay？（）A
the time required from receipt of the incoming frame， until the frame/packet has been queued for transmissionB
the time taken for a single packet to traverse the physical medium from one end to the otherC
the time taken to place a frame on the physical medium for transportD
the time spent for a packet to reside in the output queue of a router
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The expansion tank should be topped offB
The thermostatic water regulating valves should be manually openedC
The fuel filters should be changedD
The engine should be turned over slowly with the indicator cocks open
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单选题Pistons of marine medium speed diesel engines may be made of （） in order to keep the weight down for balancing purpose at high speed.A
leadB
forged steelC
alloy steelD
aluminum alloy
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单选题Most medium and slow speed diesels are started by what medium?（）A
Electric starting motorsB
HydraulicsC
Compressed airD
Ether
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