单项选择题 Generally the gudgeon pin is fully floating in both connecting rod small end and （）.

单项选择题 Generally the function of lubrication is to form of a film of lubricant between any two surfaces that have relative （）, so that surfaces dont get touch with each other.

单项选择题 Fuels of high quality with their earlier ignitions will cause higher （）pressure in cylinders of a diesel engine.