This is the 532nd most frequent Italian word.
mostrato
"Mostrato" means "shown" in English.
In this sentence, 'mostrato' is the past participle form of the verb 'mostrare' (to show) and is used in the past tense with the auxiliary verb 'ha' (has) to indicate an action completed by the subject, 'l'insegnante' (the teacher).
L'insegnante ha mostrato agli studenti un video educativo.
The teacher showed the students an educational video.
The word 'mostrato' in this context is part of a conditional perfect construction, implying that the action of showing is mentioned as an unfulfilled obligation or expectation in the past.
Avrebbe dovuto essere mostrato prima della presentazione.
It should have been shown before the presentation.
Here, 'mostrato' is used in the passive voice to signify that the action of showing was performed on the subject 'mi' (me) by an unspecified agent.