单项选择题
In the process of the stand-by, warm-up the engine usually through give preheat of which parts of the diesel engine?（）
A.cooling water of the cooling system B.fuel of the FO system C.LO of the LO system D.cooling water of the cooling system and LO of the LO system
单项选择题 The main purpose of warming the parts of the main engine is （）
单项选择题 The main purpose of starting the diesel engine on air briefly is（）
单项选择题 The purpose of engine stand-by is that （）
