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單項(xiàng)選擇題

In a normally operating diesel engine, the main cause of lubricating oil contamination in the crankcase is a result of the （）.

A.metal particles loosened by wear
B.air when no air cleaners are used
C.condensation of water vapors
D.breakdown of the lubricating oil by dilution

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單項(xiàng)選擇題

The amount of fuel injected in a particular time, or degree, of crankshaft rotation is termed （）.

A.metering
B.timing
C.rate of injection
D.rate of distribution

單項(xiàng)選擇題

A crankshaft whose center of gravity coincides with its center line is said to be （）.

A.dynamically balanced
B.statically balanced
C.counter balanced
D.resonantly balanced