单项选择题
The air supplied to the cylinders by a turbocharger is often reduced in volume by a/an （）
A.air compressor B.diffuser C.after-cooler D.ventilator
单项选择题 Which of the listed set of conditions indicates early fuel injection timing?（）
单项选择题 When fuel is injected in a diesel engine cylinder too early, （）
单项选择题 The purpose of an after-cooler is to（）
