French language Q&A Forum

Why is "celle" the correct answer  to this

 "J'aime ta robe mais je préfère ________ que Laura porte," 

rather than "laquelle"?

Aren't they both pronouns identifying one among others?

In the above examplers, it shows both "payeras" and "paieras" as being valid.

So why is "Je m'ennuierai à cette fête" considred correct, while "

Je m'ennuyerai à cette fête" was not?

Is it only "-ayer" verbs that allow the two alternatives?

Why isn't it

Aussiot que nous arrivions..

They are reminiscing and describing things so i didn't think passe compose 

I understand that one would say 'Je suis avocat(e)'; if referring to a he/she/they, does this require 'le'/'la'/'un'/une'??