单项选择题
Valve gear knocks are more easily located while the engine （）.
A.is running B.stops C.is repaired D.lacks of oil
单项选择题 VIT means （）
单项选择题 Under manoeuvring condition the main engine may run on （）.
单项选择题 Two-stroke engine turbocharging is achieved by two distinct methods, （） termed the constant pressure and the pulse system.
