7. How long has this been going on (5:54) 4. How long has this been going on? How long has this been going on(这会是多久) How long has this been going on?(还要持续多久) 8.How long has this been going op? How long has this been going on How long has this been going on? How long has this been going on（这会是多久） How long has this been going op?