单项选择题
A.decrease the time required between cleanings
B.removes all large and small foreign objects
C.ensure a positive flow of oil at all times
D.ensure that all lube oil has been treated twice
单项选择题 If the cooling water temperature and the lube oil temperature in a diesel engine are too high, the cause can be （）
单项选择题 The reversing cams of some four-stroke/cycle diesel engines are brought into position by （）
单项选择题 A diesel engine is equipped with an isochronous hydraulic governorA decrease in load will cause the engine speed to （）