单项选择题
A.the master
B.the chief engineer
C.the bridge
D.the company superintendent
单项选择题 Before engaging the turning gear and turning the diesel engine, which of the following operation should be done except（）
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（）