单项选择题
Before engaging the turning gear and turning the diesel engine, which of the following operation should be done except （）
A.open the indicator cocks B.supply some LO to cylinder liner wall with lubricator C.put the fuel handle in the "stop" position D.pump up the air bottle
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?（）
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（）
