单项选择题
In a typical fuel oil system, the oil is stored in tanks in the double bottom from which it is pumped to （） and heated.
A.a service tank B.a collecting tank C.a sump D.a settling tank
单项选择题 In a purifier, the interface between the liquid seal and the oil should be positioned as close as possible to （）.
单项选择题 In a purifier changing to a gravity disc with larger hole diameter will move the interface towards the （）.
单项选择题 In a marine diesel engine the oil sump is （）.
