"You have changed a lot."
Translation:Tu as beaucoup changé.
"beaucoup" is not an adjective, but an adverb.
In this sentence, the tense is compound past ("vous avez changé").
Here is a link that explain the rules to determine the place of adverbs in French:
Short adverbs that modify a verb usually follow the conjugated verb. (Remember that in compound tenses, the auxiliary verb is the conjugated verb, so the adverb follows that.)
Nous mangeons beaucoup.
Nous avons beaucoup mangé.
Would "tu as beaucoup changee" work if I were talking to a girl? Duo did not accept this. Please help... I've always been very confused with this for other questions as well and I'm not sure if they are simply errors or if my French is really terrible!!
Update: I just found out that I was wrong!! Because the verb only agrees with gender/plurality with the auxillary verb "etre" and not with "avoir" (as in this case).
Just updating for anyone who's confused
i.e. Il a changé --> Elle a changé --> Ils ont changé (He/she/they has/have changed)
but Il est parti --> Elle est partie --> Ils sont partis (He/she/they has/have left)
Read more here: https://www.duolingo.com/comment/38735
Why does it not accept my vous-avez, there is no way for us to know whether they are adressing a single person, a crowd, or a superior based on the english versiin.
Did you hyphenate? If so, that's probably the problem. It accepted "Vous avez beaucoup changé." To form a question ("Have you changed a lot?") I think you would reverse and hyphenate: "Avez-vous beaucoup changé?"