Every teacher and every grammar books was teaching me about using the 'asking words' (where, who, when) and generally - making the questions. I learnt that is very-super-important to write (for example) 'where were you going to', not 'where you were going to' and if you write it incorrect, after death you will go to Mordor.
But there were also sentences like 'what happened?'. And I understand it. It's no subject/person here, so 'to happen' is in its past form. Ok.
But now, when I watch English films, I very often hear 'you knew?!' or 'it's truth?' or 'you did it?'. I realised it mostly wasn't an answer or the answer was 'yes'. So my question is: are this kind of questions rethorical or it's an everyday language?