Learn Hardcore Italian: Avrei potuto parcheggiare dietro la banca, ma il posto era già occupato. - I could have parked behind the bank, but the spot was already taken.

It’s the condizionale passato (past conditional) of potere. Literally it means “I would have been able to park.” You use it to express a hypothetical ability in the past that didn’t actually happen.

What is the grammatical structure of avrei potuto parcheggiare?

It breaks down as:

avrei = “I would have” (first-person singular present condizionale of avere)
potuto = past participle of potere
parcheggiare = infinitive “to park”
Together they form the condizionale passato.

Why not say non ho potuto parcheggiare (“I couldn’t park”) instead?

Non ho potuto parcheggiare (passato prossimo) simply states you were unable to park. It doesn’t convey that you could have parked but didn’t. Avrei potuto parcheggiare emphasizes that the option existed, but you didn’t take it because the spot was already taken.

Why is it dietro la banca and not dietro banca or dietro alla banca?

Spatial prepositions like dietro, sopra, sotto normally require the definite article: dietro la banca. You can also say dietro alla banca (where alla = a + la), but dropping the “a” is more common and concise.

What does il posto refer to in this sentence?

Here posto means parking space/parking spot, not just “place” or “seat.”

Why is era già occupato used? What does già emphasize?

Era occupato = “it was occupied/taken.” Adding già (“already”) highlights that by that moment the spot was already occupied.

Could occupato ever change to occupata, occupati, or occupate?

Yes—participles agree with the noun. Posto is masculine singular, so occupato is correct. If you spoke of le piazzole (feminine plural), you’d say erano occupate.