We make the third conditional by using the past
perfect after 'if' and then 'would have' and the past
participle in the second part of the sentence:
Uses
To speak of events in the past, which had otherwise occurred, would have had other consequences. This is a
hypothetical situation in the past. We are imagining what could have happened. If I had had enough money, I
would have bought you a house
Estructure
Affirmative: If + Past Perfect + Subject + Would Have + Verb Participle
Negative: If + Past Perfect + Subject + Wouldn't Have + Verb Participle
Question: If + Past Perfect + Would +Subject + Have + Verb Participle + ?
Examples
-What would you have done if you had been in my shoes?
/¿Qué hubieras hecho si te hubiera ocurrido a ti?
-Yesterday she played the lottery and she did not win. If
she had won the lottery, she would have booked holidays
in the Caribbean. /Ayer ella jugó a la lotería y no ganó. Si
ella hubiera ganado la lotería, hubiera reservado unas
vacaciones en el Caribe. -If I had studied medicine he
would have been a very good doctor./Si él hubiera
estudiado medicina, hubiera sido un gran doctor.
The third conditional in English helps us to
express conditions and their consequences in a
hypothetical future and if the past had been
otherwise.