单项选择题
A.reduce fuel weight
B.increase specific gravity
C.separate fuel from lube oil
D.reduce fuel viscosity
单项选择题 In a diesel engine, blow-by is generally the result of worn（）
单项选择题 For optimum results, centrifugal purification of heavy fuel oil should be accomplished with the fuel at the lowest practicable（）
单项选择题 Diesel engine piston ring blow-by is usually caused by excessive ring clearance at the ring（）