单项选择题
The function of lubricating oil is to （）
A.maintain even distribution of bearing wear B.maintain a constant oil temperature C.maintain a pressurized film between moving surfaces D.remove entrained water
单项选择题 Main propulsion engine lube oil sumps should be constructed （）
单项选择题 The ash content of a fuel oil is significant to the operating engineer because it （）
单项选择题 The shape of a cam on a diesel engine determines the valve’s （）
