The third conditional expresses a past regret or shows a different outcome that would have happened if a certain condition had been met.
To form the third conditional we use if + had + past participle, would/might/could + have + past participle
Let’s see some examples:
👉 If I had arrived on time, no one would have stared at me as I walked in → Si hubiese llegado a tiempo, nadie me habría mirado al entrar
👉 If you had brought your jacket, you would not have been so cold last night → Si hubieses traído tu chaqueta, no habrías cogido frío anoche
👉 If they had not missed the bus, they would have got to work on time → Si no hubiesen perdido el bus, habrían llegado a tiempo a trabajar
👉 If Andrew had not broken his leg, he would not have missed the dance → Si Andrew no se hubiese roto la pierna, no se habría perdido el baile
👉 If Maya hadn’t caught a cold, she would’ve come over after school → Si Maya no hubiese cogido un resfriado, hubiese venido después del colegio
Remember! If a sentence begins with an if clause it is followed by a comma