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單項(xiàng)選擇題

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

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單項(xiàng)選擇題

The （） of an oil refers to its ability to mix with water and then release the water in a centrifuge.

A.oxidation resistance
B.carbon-forming tendency
C.demulsibility
D.acidity

單項(xiàng)選擇題

Obviously, for a given fuel oil, its pour point is （） its cloud point.

A.lower than
B.higher than
C.as same as
D.better than

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