French language Q&A Forum

I am having a difficult time deciding when devoir is appropriate and when it is not.  All the other applications, I am ok with.  But if devoir implies "must have" why is a purse a necessity? Why not just Avoir besoin?  And why is sleep NOT a necessity (or I may be getting this confused at this point). This is getting to be more of a guessing/memorization thing than an actual understanding thing.  I see from the previous posts that this has been discussed ad infinitum so it's not just me.  Any easy way to decide when to use devoir and when NOT to use it in this context?

Thanks

Can one also say 'dont les Celtes' in this situation?

I put "passé" rather than "passée" - usually a straightforward mistake - but on this occasion, I'm thinking and thinking, but I can't see what it is that "passée" is agreeing with. La soixantaine? Or Forme physique? And if so, why ?

Why doesn’t the past participle take an extra ‘s’ with ‘nous’. Isn’t there more than one person, like ‘ils’? 

What is wrong with saying “j’ai trouvé 

leur livre” for “I found their book”? Isn’t it the same as “j’ai trouvé le livre des enfants “?

Why is it "je te l'avais dit" and not "je te l'ai dit!"?

Thanks!

I've been wondering if there are definite rules as to whether one adds a "de" sometimes, but sometimes I go awry with an incorrect guess. At present it seems to me that a noun after the second "de" is safe enough. Am I right? The help from the quick lessons is immensely helpful, but thus far I haven't found one which would solve my problem with rules for the 'De's'.

Clive 

Why is tu t-appelles Gary incorrect please ? 🤔

Small mis-spelling.

“and I set the table with colourful plates.”

“et j'ai mis la table avec des assiettes multicolres.”

-> “multicolores”