Third Conditional

Condition | Result | |
Past Perfect | WOULD HAVE + Past Participle | |
If | I had gone to my mom’s house | I would have sang with my brothers. |
In the third conditional the time for the specific condition to occur is gone. In the example above you did not go to your mom’s house where your brothers were signing. You may go to your mom’s house in the future, but that one opportunity has passed. We use the past perfect tense to refer to the past condition. We use WOULD HAVE + past participle to refer to the outcome that could not have happened. In this conditional, both the original condition and the outcome are impossible.
In the third conditional the words would have can be replaced by should have, could have, or might have. For example: If you had put gas in the car, we could have made it to the airport. More examples are listed below:
IF | Condition | Result |
past perfect | WOULD HAVE + past participle | |
If | I had heard her | I would have gone. |
If | John had jumped | he would have made the shot. |
If | she had seen the spot | she would have parked there. |
If | it had snowed yesterday | they would have closed public transportation. |
If | it had rained at graduation | where would you have gone? |
Also, you can switch the order of the clauses(result and condition) along with the if statement:
Result | IF | Condition |
WOULD HAVE + past participle | past perfect | |
I would have gone | if | I had heard her. |
John would have made the shot | if | he had jumped. |
She would have parked there | if | she had seen the spot. |
They would have closed public transportation | if | it had snowed yesterday. |
Where would you have gone | if | it had rained at graduation? |