单项选择题
During the power stroke of a four-stroke/cycle diesel engine, most of the side thrust of a trunk-type piston is absorbed by the（）
A.piston skirt B.pinion C.crosshead D.compression rings
单项选择题 A pyrometer is an instrument commonly used to measure（）
单项选择题 Worn main bearings in a diesel engine can result in （）
单项选择题 When monitoring diesel engine performance, the most useful instrument to use is the （）
