The third conditional

• What it is
• More examples
• Could have / might have instead of would have
• Questions and negative sentences
• Summary of all three conditionals
• Mixed conditionals
  • Past cause, present result
  • Present cause, past result

What it is

The third conditional is used to talk about imaginary situations in the past. Things that didn't happen, and their imaginary consequences. It is built with if + past perfect, followed by would have + past participle.

If I had studied harder, I would have passed the exam.

If she had taken the train, she wouldn't have been late.

The action didn't happen. We are imagining a different past.

More examples

If I had known about the party, I would have gone.

If we had left earlier, we would have caught the flight.

If he hadn't eaten so much, he wouldn't have felt sick.

If it hadn't rained, we would have gone to the beach.

Could have / might have instead of would have

We can use could have or might have instead of would have:

If I had arrived earlier, I could have helped.

If she had applied, she might have gotten the job.

Questions and negative sentences

What would you have done if you had missed the train?

If I hadn't moved to this city, I wouldn't have met my wife.

Summary of all three conditionals

First: *If* + present, *will* + infinitive => possible future
If it rains, I'll stay home.

Second: *If* + past simple, *would* + infinitive => imaginary present/future
If I had more money, I would travel.

Third: *If* + past perfect, *would have* + past participle => imaginary past
If I had studied, I would have passed.

Mixed conditionals

Sometimes we mix the second and third conditionals. This happens when an imaginary past action has a present consequence, or vice versa.

Past cause, present result

If I had studied medicine, I would be a doctor now.

Structure: if + past perfect, would + infinitive.

Present cause, past result

If I were taller, I would have played basketball in college.

Structure: if + past simple, would have + past participle.