French language Q&A Forum

Can anyone explain what the difference between the passe compose and past perfect forms of devoir are? google translate shows them as being the same thing:

J'ai dû faire quelque chose     -> I had to do something

J'avais dû faire quelque chose  -> I had to do something

Similarly what is the difference between the future and conditional forms:

j'aurai dû faire quelque chose  -> I should have done something

j'aurais dû faire quelque chose -> I should have done something

Thanks!

explain the use of the infinitive with conditional. I don't understand.

Something I've been noticing throughout the lessons is that there does not seem to be a rise in intonation at the end of the questions in the French pronunciation (see example above in: "Vous ne devriez pas etre a l'ecole"). Instead, the intonation sounds more like a statement. Do the French not have an uplift in intonation at the end of spoken questions?

I am wondering how to form a statement using would (le conditionnel?) from a past perspective.  As in "I spent a lot of time deciding what I would eat for lunch today".  Could someone tell me if the below is correct?  Apologies for the spelling/accent errors as I am typing on a computer where i don't know how to type those, but i've tried to approximate the critical ones below.

j'ai passe' beaucoup de temps `a decider quoi je mangerais pour dejeuner aujourd'hui.

Or

maybe i should say "quoi j'allais manger pour..."?

Merci d'avance.

For some reason I can't reply to a specific response, so I'll have to post this as a seperate comment. 

This is a follow up question to Laura's translation of "She ought to really stop seeing him", which she wrote as "Elle devrait vraiment arreter de le voir." I'm wondering if the phrase "Elle devrait vraiment s'arreter de le voir" is also acceptable.