voulais vs as voulu

Question

Why couldn't I say "as voulu" for "why did I want a dog?

Accepted Answer

Hi Camille, 
The modal verb 'vouloir' is very seldom used in the passé composé ( which describes completed actions) and more often in the imparfait because it is used to indicate ongoing states or habitual actions in the past.
"Vouloir" often describes a continuous state of wanting or desiring, making the imparfait more suitable.
I tried to think of many examples where the passé composé would work but the imparfait sounded just as correct to me.
I did find one which is a set expression -
Ah, tu l'as voulu !
which translates as = Ah, you asked for it! /You got what you wished for !/You brought this on yourself!
Hope this helps!

Answer

Bonjour Camille,The question asked in the lesson is "Why did you want a dog?" This is an imparfait situation because "did" is being used rather than "do" (As in: Why do you want a dog?).Therefore this could be written "Pourquoi vouliez-vous .... " or "Pourquoi voulais-tu ...."Your proposal suggests a Passé Composé construction but the situation is not a completed past action.I hope you find  this helpful.Bonne continuationJim