In the sentence "Ils quittent le travail à 19 heures." if the verb was replaced by partent or sortent would that change the meaning, or just be wrong?

Hi Patrick,

Partir does not require a direct object as an intransitive verb.

Sortir with a direct object means to take something out.

So I say no! These two verbs would not be appropriate in the sentence you have quoted in your query.

Quitter is the verb most appropriate in the sentence you have quoted above as it requires a direct object to complete the meaning.

Hope this helps.

Jim

Thanks, Jim,  for your very clear answer