I dont know what youreon about.
怎么样理解这里的onaboutwhat?
be on about sth.是惯用短语,假如必须要剖析的话,on是副词作表语,about构成介词短语作方面状语。你查一下词典就了解了。譬如《牛津高阶英汉双解词典》
be/go/keep on about sth talk in a boring, tedious or complaining way about sth唠叨; 抱怨: Whats he on about now? 他在絮叨什麽?
又如:
Honest, Kate, I dont know what youre on about. 说实话,凯特,我不了解你在怎么说。《麦克米兰英语词典》