单项选择题
The engine has one or two group of fuel pumps, depending upon （）.
A.the number of fuel valves B.the number of cylinders C.the speed of engine D.the power of engine
单项选择题 The energy for pushing this piston up can be supplied from （）, so that the piston can keep moving up and down.
单项选择题 The efficiency of turbocharge system is increased by fitting a charge air cooler （） the compressor.
单项选择题 The distance from TDC to BDC of the diesel engine is called （）.
