go after means follow somebody (e.g. My brother tried to go after the thief in his car.)
go after something means try to achieve something (e.g. I went after my dream and now I am a published writer.)
go against means compete or oppose (e.g. We are going against the best soccer team in the city tonight.)
go ahead means start or proceed (e.g. Please go ahead and eat before the food gets cold.)
go back means return to a place (e.g. I have to go back home and get my lunch.)
go off means explode (e.g. A bomb went off in the city centre, but fortunately nobody was hurt)
go on means continue (= carry on with something) (e.g. We can’t go on spending money like this. We’ll have nothing left soon.)
go on means happen (e.g. What’s all that noise? What’s going on? (= what’s happening?))
go on with/ carry on with something (e.g. Don’t let me disturb you. Please carry on with what you’re doing)
go out means leave home to go on a social event (e.g. Suddenly all the lights in the building went out.)
go out with somebody means date (e.g. Jesse has been going out with Luke since they met last winter.)
go over means review (e.g. Please go over your answers before you submit your test.)
go over means visit somebody nearby (e.g. I haven’t seen Tina for a long time. I think I’ll go over for an hour or two.)
go up/ come up/ walk up (to ~) means approach (e.g. A man came up to me in the street and asked me for money)
go without something (e.g. When I was young, we went without winter boots.)