单项选择题
What is the function of an engine’s stationary parts?（）
A.To add power to the engine B.To keep the engine firmly attached to its supporting base C.To keep moving engine part in their proper relative positions D.To rotate the crankshaft
单项选择题 An overcorrecting and unstable engine governor operation is known as（）.
单项选择题 Coolant can be lost from a diesel engine jacket cooling waster system by leakage from（）
单项选择题 Ring groove inserts are occasionally used on aluminum alloy piston to（）
