单项选择题 The cylinder oil will have to neutralize the acidic products of combustion and have good （） properties to keep the metal surfaces clean.

单项选择题 As for turbine oil, contact with water in the form of steam will be inevitable so good （） properties will be essential.

单项选择题 Any carbon built up on surfaces must be washed away by （） additives and held in suspension by a （） additive.