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單項(xiàng)選擇題

In conventional systems, the injection pressure(), while it’s()in common rail diesel engines.

A.fluctuates with the engine speed to some extent, independent of the engine speed
B.keeps constant at all engine speed, dependent on the engine speed to some extent
C.keeps constant at all engine speed, independent of the engine speed
D.is decided by the engine speed, constant at all engine speed

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