Il passato prossimo con essere
Most verbs build the past with avere (lesson 16), but a closed group of verbs uses essere instead β and when they do, the past participle agrees with the subject in gender and number, just like an adjective. Marco Γ¨ andato a Roma (m sg.) vs Anna Γ¨ andata a Roma (f sg.) vs Anna e Maria sono andate a Roma (f pl.). The verbs in this group are roughly: motion (andare, venire, partire, arrivare), change of state (diventare, nascere, morire), and all reflexives.
The recipe: essere + past participle (that agrees)
Conjugate essere for the subject (lesson 3: sono, sei, Γ¨, siamo, siete, sono) and add the past participle. The participle then ENDS shift to match the subject: -o (m sg), -a (f sg), -i (m / mixed pl), -e (f pl). Marco Γ¨ arrivato. Anna Γ¨ arrivata. I ragazzi sono arrivati. Le ragazze sono arrivate. The participle is acting like an adjective on the subject. With avere (lesson 16) it does NOT change β only with essere.
Which verbs take essere β verbs of motion and change
Movement and arrival/departure: andare β andato (gone), venire β venuto (come), arrivare β arrivato (arrived), partire β partito (left), uscire β uscito (gone out), entrare β entrato (entered), tornare β tornato (returned), salire β salito (gone up), scendere β sceso (gone down). Change of state or being: nascere β nato (born), morire β morto (died), diventare β diventato (become), rimanere β rimasto (stayed), restare β restato (remained), stare β stato (stayed/been), essere itself β stato (been β same word as stare).
Reflexives always take essere
Every reflexive verb (lesson 15) builds its past with essere, and the participle agrees with the subject. Mi sono alzato/a = I got up. Ti sei svegliato/a? = Did you wake up? Marco si Γ¨ lavato. Anna si Γ¨ lavata. Ci siamo vestiti (mixed/m). Le ragazze si sono vestite (f pl). The reflexive pronoun stays right where it always was β between any non and the helper: Non mi sono alzato presto = I didn't get up early.
Same verb, different helper, different meaning
A few verbs use avere OR essere depending on whether they have a direct object. The most common is passare: Sono passato a Milano = I passed through Milan (motion β essere). Ho passato due ore al bar = I spent two hours at the cafΓ© (transitive β avere). Same with cambiare: Γ cambiato = he's changed (state) vs Ho cambiato la macchina = I changed the car. Don't drill it now β just notice that meaning sometimes flips the auxiliary.
Stato β one participle for two verbs
stato is the past participle of BOTH essere (to be) AND stare (to stay/feel). And both take essere as their helper. So sono stato a Roma can mean 'I have been to Rome' (essere) or 'I stayed in Rome' (stare) β context decides. Like every essere-participle, it agrees: Anna Γ¨ stata a Roma (f sg). This is the standard way to say 'I have been somewhere' in Italian β there's no separate construction for it.
