What do you mean, ‘used to’?
Re: Cho: A Gryffindor will stand beside you when life is hard as long as you are never weak, as Marietta was weak. A Slytherin will stand beside you as long as you are never beyond use, as Wormtail became useless. A Hufflepuff will stand beside you, because to a Hufflepuff it doesn't matter who you are; you deserve someone to stand with you. A Ravenclaw will stand beside you because it *does* matter who you are, and a Ravenclaw, and only a Ravenclaw, cares why you did it, no matter what you did.