单项选择题
The majority of medium speed and high speed marine diesel engines for main or auxiliary drive operate on the （） cycle.
A.two-stroke B.four-stoke C.long-stroke D.short-stroke
单项选择题 The main moving parts of a diesel engine consist of the （） and the pistons.
单项选择题 The main function of the lubrication system in to enable （） of a film of oil between the moving parts.
单项选择题 The main factor which determines the output of each cylinder is （）
