单项选择题
A.Viscosity is decreased
B.Octane number is altered
C.Pump speed is decreased
D.Blower’s speed is decreased
单项选择题 It is easier to replace a dry cylinder liner than a wet one because（）
单项选择题 Which of the turbo-charging methods listed directs the exhaust gases to the turbine at fairly uniform velocity and pressure?（）
单项选择题 Which of the following problems will occur if the needle valve in a fuel injection nozzle sticks in the open position?（）