单项选择题
The treatment of the fuel oils involves storage, heating, filtering and（）
A.centrifuging B.pressurizing C.atomization D.igniting
单项选择题 When anaerobic bacteria convert the sewage to an inert sludge,（）
单项选择题 Bacteria which live are said to be aerobic（）
单项选择题 It is that reduce the BOD by converting the organic content of the sewage to a chemically and organically inert sludge（）
