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 CYL Oil to cylinder liner wall with lubricator (only for two stoke diesel engine) C.put the fuel handle in the “stop” position D.pump up the air bottle
单项选择题 The seven segment arrangement for numerical(数字的) display on consoles, test meters and other applications can be either（）
单项选择题 Usually, emergency electricity supplies to on board（）
单项选择题 Before doing any work on a hydraulic system equipped with accumulators, you should（）
