（） in what position the engine stops there will always be at least one of the cylinders with its starting air valve open to admit compressed air to start the engine.

A.The driven gear
B.The drive
C.The grease
D.The lubricating oil

A.Distilled
B.Distilling
C.Boiling
D.Boiled

A.Between；more commonly
B.Among；the most commonly
C.Between；not more commonly
D.Among；not the most commonly