单项选择题
The remaining oil in the lubricating pipes and ducts should be blown out with （）.
A.atmosphere B.the fresh water C.compressed air D.chemical compounds
单项选择题 The quantity of oil injected into the cylinder can be regulated （）.
单项选择题 The purpose of the flywheel of a diesel engine is to （）.
单项选择题 The pumps press oil into the cross-head bearing gap when the load on the shell is at its lowest What is the meaning of “its” in the sentence above?（）
