（） or air venting arrangement is fitted to the fuel supply passage.

（） neutralizes the acid conditions and（） cleanses the rings and grooves.

A.The detergency；the alkalinity
B.The alkalinity；the detergency
C.The inhabitant；the water
D.The additives；the distilled water

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（） is usually driven by the engine camshaft and supplies pilot air to the cylinder air start valve.

A.An air receiver
B.An operating valve
C.An automatic valve
D.An air distributor

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