单项选择题
A diesel engine is warmed up and white vapor is in the exhaust，this could indicate （）
A.excessive cylinder lubrication B.a lugging engine C.a leaking cylinder liner D.overloading of one cylinder
单项选择题 The main operating characteristic of diesel engines which distinguishes them from other internal combustion engines is the （）
单项选择题 Turbulence is created in the cylinders of a diesel engine to （）
单项选择题 The ratio of the brake horsepower to the indicate of a diesel engine is its （）
