Learn French: Toutes les filles sont arrivées pour le départ, sauf toi. - All the girls arrived for the departure, except you.

In the passé composé, verbs that use être as their helper verb must make their past participle agree with the subject. Because the subject here is les filles (feminine and plural), we add an -e for feminine and an -s for plural to the past participle arrivé, making it arrivées.

Why is it Toutes and not Tous?

The word for 'all' has to agree with the noun it describes. Since filles is feminine plural, we use the feminine plural form Toutes. If the subject were masculine plural, like 'all the boys', it would be Tous les garçons.

Why is it sauf toi instead of sauf tu?

In French, you must use a stress pronoun (like moi, toi, lui, elle) instead of a subject pronoun (like je, tu, il, elle) when it follows a word like sauf (except), pour (for), or avec (with).

Is le départ related to the verb partir?