to be about or connected with sb/sth :
'What do you want to see me about?' 'It's to do with that letter you sent me.'
to be about or connected with sb/sth :
'What do you want to see me about?' 'It's to do with that letter you sent me.'
Oxford Advanced Learner's English Dictionary. Оксфордский английский словарь для изучающик язык на продвинутом уровне. 2005