单项选择题
Any carbon built up on surfaces must be washed away by （） additives and held in suspension by a （） additive.
A.dispersant；detergent B.detergent；dispersant C.dispersant；dispersant D.detergent；detergent
单项选择题 The （） of an oil refers to its ability to mix with water and then release the water in a centrifuge.
单项选择题 Obviously, for a given fuel oil, its pour point is （） its cloud point.
单项选择题 The higher the cetane number, （） the ignition quality of the fuel.
