Rule reminder
'Sentire' = to hear/sense (passive, automatic perception). 'Ascoltare' = to listen (active, deliberate attention). 'Udire' = to hear (formal/literary register, often used in legal or elevated contexts). The key distinction: you can 'sentire' a noise without choosing to; you 'ascoltare' when you direct your attention.
Ho _____ un rumore strano di notte, ma non sapevo cosa fosse.