go on (at someone, about something)
(This phrasal verb has more than one meaning)
Definition: to continue talking to someone about the same thing, in an annoying or boring way.
E.g.1: She went on at her father until he agreed to buy her a new dress.
E.g.2: It was a very boring talk – he went on about his theories for over an hour!
This phrasal verb cannot be separated.