Where does my brother live?

Does my brother live in London?

What did they buy last year?

Which house did they buy last year?

(если вы имеете в виду "хвостики" то есть tag questions)

He is dancing well, isn't he?

They bought this new house last year, didn't they?

Ответ:

1) does my brother live in London?

where does my brother live?

2) when did they buy the new house?

they bought the new house, aren't they?

did they buy the new house?

3) does he dance well?

does he dance well or bad?

he is dancing well, doesn't he?