Main engines as well as auxiliary engines operating on heavy fuel should have continuous on the lubricating oil, either according to the bypass or batch principles（）

These acid residues must be prevented from entering the...

单项选择题These acid residues must be prevented from entering the crankcase, otherwise the lube oil would be（）

（）on board ship are used to control and distribute the ...

单项选择题（）on board ship are used to control and distribute the electrical energy generated by generators.

The heavy-duty lubricating oil with chemical has been w...

单项选择题The heavy-duty lubricating oil with chemical has been widely introduced in recent years（）