حَضَرَ الْمُعَلِّمُونَ.
Translation: The teachers arrived.
حَضَرَ: past-tense verb, fixed with fatḥa.
الْمُعَلِّمُونَ: subject, nominative with wāw because it is a sound masculine plural.
Why? Its subject position requires the nominative, and wāw is the nominative sign for this noun class.