单选题Proper lubrication of the main bearings is more easily obtained in a single acting, four-stroke/cycle diesel engine than in a tow-stroke/cycle diesel engine because（）.AThe direction of pressure on the journal in four-stroke engine is continuouslyBpositive feed lubricators are installed on all bearings of four-stroke engine, whereas as a splash feed system is used on tow-stroke engineCfour-stroke engines usually utilize a heavier grade of oil than tow-stroke enginesDLow-stroke engines usually consume less lube oil than four-stroke engines
单选题
Proper lubrication of the main bearings is more easily obtained in a single acting, four-stroke/cycle diesel engine than in a tow-stroke/cycle diesel engine because（）.
A
The direction of pressure on the journal in four-stroke engine is continuously
B
positive feed lubricators are installed on all bearings of four-stroke engine, whereas as a splash feed system is used on tow-stroke engine
C
four-stroke engines usually utilize a heavier grade of oil than tow-stroke engines
D
Low-stroke engines usually consume less lube oil than four-stroke engines
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