单项选择题
Black smoke exhausting from an operating diesel engine can be caused by （）
A.fuel dribbling from leaking fuel injectors B.burning fuel with a high carbon content C.burning fuel with a high vanadium content D.burning fuel with a lower sulphur content
单项选择题 White smoke exhausting from a diesel engine can be caused by a （）
单项选择题 White smoke exhausting from a diesel engine can be caused by （）
单项选择题 White smoke issuing from the exhaust of an auxiliary diesel engine valve opening （）
