单项选择题
These acid residues must be prevented from entering the crankcase, otherwise the lube oil would be（）
A.contaminated B.emulsified C.deteriorated D.oxidated
单项选择题 （）on board ship are used to control and distribute the electrical energy generated by generators.
单项选择题 The heavy-duty lubricating oil with chemical has been widely introduced in recent years（）
单项选择题 Great care is dedicated to the removal of from the scavenge air（）
