单项选择题 The words such as quantity, grade, viscosity and specific gravity should be in the （）.

单项选择题 The withdrawing of the cylinder liners, in general, depends on their （）.This may amount to approximately 1/120 of the diameter in some engines.

单项选择题 The way to reduce （） is to build up a film of lubricant between any two surfaces that rub against each other.