单项选择题
If the analysis of used lube oil indicates a high content of iron particles, this could indicate（）
A.corrosive deterioration of a bearing B.inadequate air filtration C.excessive ring and liner wear D.excessive cooling of lubricating oil
单项选择题 Late fuel injection timing is indicated by （）
单项选择题 The process of supplying a diesel engine cylinder with air at a pressure greater than atmospheric is called（）.
单项选择题 In a diesel engine, blow-by（）
