Essere or avere? Choosing the Italian auxiliary verb

Every passato prossimo needs an auxiliary, a helper verb that goes before the past participle: either avere («ho mangiato») or essere («sono andato»). English always uses “have”, so choosing between the two is the most common mistake learners make in the Italian past.

The good news is that, for the vast majority of verbs, the choice depends only on the verb. Most verbs take avere. A smaller, well-defined group takes essere: verbs of movement, of staying and of change, plus every reflexive verb. The participle itself is the same with either auxiliary (regular -ato, -uto, -ito, or irregular like fatto and visto), but with essere its ending must agree with the subject: «Sara è partita», «i ragazzi sono partiti».

Avere: verbs with a direct object, and many more

A direct object is the person or thing that receives the action directly, with no preposition before it. To find it, ask che cosa? (what?) or chi? (whom?) after the verb. In «Ho comprato il pane», the answer to “bought what?” is «il pane», so comprare has a direct object. Verbs that can take a direct object, called transitive verbs, use avere in the passato prossimo even when the object is not said: «Hai mangiato?» “Have you eaten?”

Avere is also the auxiliary for many verbs that usually have no object and describe an activity: dormire, lavorare, parlare, telefonare, ridere, piangere, viaggiare, camminare, nuotare, passeggiare. The last four involve moving, yet they take avere: they describe the activity itself, not a trip from one place to another. Compare «Ho camminato per due ore» “I walked for two hours” with «Sono andato al parco» “I went to the park”.

With avere, the participle does not agree with the subject: «Sara ha lavorato», «i ragazzi hanno lavorato».

• Abbiamo visitato il museo e abbiamo mangiato in centro. · We visited the museum and ate in the centre.
• Ieri ho lavorato fino a tardi. · Yesterday I worked until late.
• Hanno viaggiato in treno per tutta l’Italia. · They travelled all over Italy by train.

Essere: movement, staying and change

Essere is the auxiliary for verbs that describe movement from one place to another: andare, venire, arrivare, partire, tornare, entrare, uscire, cadere. It is also used for staying where you are (stare, restare, rimanere) and for a change of state, where someone or something becomes different: nascere, morire, diventare, crescere. Essere itself takes essere: «Sono stato in Sicilia».

A few very common verbs that describe events or reactions also take essere: succedere («Che cosa è successo?»), costare («Quanto è costato?»), sembrare, and piacere («Il film mi è piaciuto»). With piacere the participle agrees with the thing that is liked: «Le lasagne mi sono piaciute».

With essere, the participle always agrees with the subject: -o, -a, -i or -e. A mixed group of men and women takes -i: «Paolo e Sara sono arrivati». A useful tip: almost all essere verbs have no direct object, but not every verb without an object takes essere. Dormire and lavorare have no object and still take avere. When you are unsure, a good dictionary tells you which auxiliary a verb uses.

• Sara è uscita con le amiche. · Sara went out with her friends.
• Siamo rimasti a casa perché pioveva. · We stayed at home because it was raining.
• Mio figlio è nato a maggio. · My son was born in May.

Reflexive verbs always take essere

Reflexive verbs are the ones with -si at the end of the infinitive, such as alzarsi (to get up), svegliarsi (to wake up) and divertirsi (to have fun). In the passato prossimo they always take essere, with the reflexive pronoun before the auxiliary: «mi sono alzato», «ti sei svegliata», «ci siamo divertiti».

This is true even when the same verb without -si takes avere. Compare «Ho lavato la macchina» “I washed the car” with «Mi sono lavato» “I had a wash”, or «Ho svegliato i bambini» “I woke the children up” with «Mi sono svegliata alle sette» “I woke up at seven”. As always with essere, the participle agrees with the subject.

• Stamattina Luca si è alzato alle sei. · This morning Luca got up at six.
• Vi siete divertiti alla festa? · Did you have fun at the party?

Verbs that take both: the meaning decides

A small group of verbs can take either auxiliary, and the choice changes the meaning. The rule is the same as above: with a direct object, use avere; without one, when the subject itself moves, begins, ends or changes, use essere.

The most common are cominciare and finire: «Ho finito il libro» “I finished the book”, but «Il film è finito» “The film ended”. Passare works the same way: «Ho passato una bella giornata» “I spent a nice day”, but «Sono passato in farmacia» “I stopped by the pharmacy”. So do salire, scendere and cambiare.

Correre takes avere for the activity («Ho corso per un’ora») and essere for running to a place («Sono corsa a casa»). With weather verbs, usage genuinely varies: «è piovuto» and «ha piovuto» are both correct, and you will hear both.