单项选择题
A smoking exhaust from an operating diesel engine could be caused by （）
A.low sulfur content in the fuel B.a loose injector inlet connection C.late fuel injection D.high injection pressure
单项选择题 What is commonly used to create turbulence in a diesel engine combustion system?（）
单项选择题 What causes diesel fuel to be ignited in the cylinder of an operating diesel engine?（）
单项选择题 If a diesel engine fails to start，one of the likely causes is （）
