"You changed a lot."
Translation:Tu as beaucoup changé.
I put both "Tu as beaucoup changé" and "Tu es beaucoup changé" as possible translations of "You changed a lot." Isn't "changer" one of the verbs that can be used with both auxilliaries with a difference in meaning? Wouldn't the first translation mean that the doer effected a lot of changes in something, as in rearranging the furniture in a room? And wouldn't the second translation mean that the doer had changed something about himself, as in looking older? If so, without any supplied context, wouldn't both translations be correct?
I think that although both avoir and être can be used with changé, when the doer was changed, you would say "You have changed a lot" rather than "You changed a lot" if you met him in the street. Given the reverse exercise, "You have changed a lot" could be taken to mean either that the doer had effected the change or that he was himself changed, so either avoir or être would be possible.
changer is conjugated with avoir. se changer is conjugated with être.
you would use se changer to say that you were getting changed. (from pj's to suit and tie) or that something is transforming. (water into ice).
you could use changer to say both of these things, too. and and all other uses of changer. (change diapers, change direction, exchange money, the seasons change, etc)
your "tu es ..." form would be " tu t'es beaucoup changé." i'm not sure why it wouldn't be correct, other than it isn't on the list.
I guess I have the opposite question to what people asked before, why are both these required (when choosing from multiple answers)
Tu changeais beaucoup.
Tu as beaucoup changé.
I'd have thought that "you changed a lot" would be very much corresponding to the imperfective, and if you really meant "tu as beaucoup changé" you would say "you have changed a lot".