单项选择题 The exhaust gases in a supercharged two-stroke/cycle diesel engine are expelled from the cylinder by （）

单项选择题 Which of the listed items should be secured before performing any maintenance on a solenoid operated air start valve?（）

单项选择题 A diesel engine experiences a sudden loss in speed, accompanied by black exhaust smoke, with the fuel rack at maximum, and speed remaining below normal the probable（）