Louis (corrigez-moi svp)

[steel owl]

Please be patient

Our volunteers look into many questions every day; sometimes it takes them a little while to answer.

Pro tip: you can rename the thread title with `.tr <thread name>`

Make it descriptive, including relevant context, but also to the point. This way you improve your chances of getting a more relevant and specific answer.

[waxen cypress]

The replacing in this case is only happening once

[frosty glacier]

Marie a dû le remplacer = Marie had to replace him and she did

Marie devait le remplacer = Marie was supposed to replace him (The sentence contains no information about whether or not she did end up replacing him)

It goes back to the usual difference between the passé composé and the imparfait. The passé composé describes a completed action or change of state, while the imparfait describes a state.