单项选择题
The lubricating pipes and dusts should be blown out with （）.
A.atmosphere B.the fresh water C.compressed air D.chemical compounds
单项选择题 The lubricating oil is pumped from the drain tank, very often with （） in the suction line.
单项选择题 The lube oil in the bearings is drawn from a （）, usually located in the bedplate.
单项选择题 The lowest ring of a piston is （）.
