单项选择题
On board supply vessels, a centrifuge is normally used to purify（）
A.cooling water B.fuel oil C.sea water D.diesel intake air
单项选择题 Water accumulating in the crankcase of a diesel engine could indicate（）
单项选择题 The device used to store a charged pressure for a hydraulic starting system is called the（）
单项选择题 How dose water enter the crankcase of a diesel engine?（）
