单项选择题 The sequence of parts in a generally used fuel oil supply system for a main engine is （） (1)tanks in the double bottom (2)centrifuges (3)service tank (4)settling tank (5)viscosity regulator

单项选择题 The sequence of fuel injection into cylinders is determined by （）.

单项选择题 The selection of an oil from the （） depends to a great extent on the operating conditions, the design of the engine and the type of fuel to be burned.