Third Conditional Sentences

1. Use

Third conditional sentences talk about the past. They are used to describe a situation which is given in the if-clause that didn’t happen, and to imagine the result of this situation.

2. Form

if clause main clause
Past Perfect would + have + past participle
could + have + past participle
might + have + past participle

3. Examples

if clause main clause
If I had studied, I would have passed the exams.
If I had studied, I could have passed the exams.
If I had studied, I might have passed the exams.

The if-clause can be at the beginning or at the end of a sentence.

if clause main clause
If I had studied, I would have passed the exams.
main clause if clause
I would have passed the exams if I had studied.

4. Grammar Point

The above examples in the main clauses are known grammatically as Conditional Perfect Simple It is also possible to have the main clause in a continuous tense i.e:

if clause main clause
If I had passed the exam, I would have been studying medicine

This is known grammatically as the Conditional Perfect Continuous