单项选择题
（）can cause oil flow from sludge outlet of self cleaning separator.
A.Too much sludge accumulated in separator bowl B.Diameter of gravity disc too large C.High level tank lack of water D.Oil input too rapidly
单项选择题 （）can not cause oil flow from water outlet of self-cleaning separator.
单项选择题 （）can cause oil flow from water outlet of a separator.
单项选择题 When finish work on the oil separator, you should（）firstly.
