Here is part of the libretto of Mozart’s Figaro, from a wide-ranging musicological website by composer Barry Mitchell; the other acts are probably there too. I was having trouble understanding the Count’s malediction of Cherubino towards the end of Act II (“Mora, e non sia più … “) where the first word is what a Classicist would call a jussive subjunctive — although maybe that just boils down to a perfectly regular imperative. (My Italian was picked up from the street and has big gaps.) Da Ponte’s language is disarmingly lucid, in contrast to the turgid pomposities that obscure many nineteenth-century libretti, but it is also noticeably older, with forms such as “veggio” for vedo or “leggo” for leggio that are probably perfectly good dialect in the next village over the hill where the people will knife you as soon as look at you, but wouldn’t be found any more in print. It is therefore sometimes harder than it looks. Those two descending notes have a dark colouring that fits the meaning like a glove, a fleeting effect at which Mozart excels.