单项选择题
An overcorrecting and unstable engine governor operation is known as（）.
A.droop B.dead banding C.dash potting D.hunting
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（）
单项选择题 A sudden drop in diesel engine cylinder compression pressure can be caused by（）
