单项选择题
A.centrifugal separators; the engine cylinder
B.oily water separators; the engine cylinder
C.oily water separators; the fuel supply system
D.centrifuges; the fuel supply system
单项选择题 When the heavy fuel oil is heated to achieve the viscosity of 10-15 cst, may occur.To avoid this, a system is used in most occasions（）
单项选择题 In order to improve the working conditions of the crosshead bearings, the bearing pressure is made and the peripheral speed is made in later designs（）
单项选择题 In order to control thermal stresses, some types of modern engines use pistons with（）