Fill in the blank with the appropriate past-tense form of the verb "se brosser"Il les dents.

The correct sentence is “Il s'est brossé les dents.” The passé composé of a reflexive verb uses être, so the auxiliary is “s'est,” not “s'a.” The direct object “les dents” comes after the verb, so “brossé” does not agree with it and stays in the masculine singular form.

AI-written and checked against the verified answer.