USE
We use the third conditional (Type 3) to talk about imaginary or unreal situations in the past that are different from what actually happened (often to express regrets or criticism).
If you had had more time, you would have finished this project.
(But you didn't have more time, so you didn't finish this project.)
FORM
1. The third conditional sentences consist of two parts: the if-clause and the main clause.
E.g.
If you had had more time, you would have finished this project.
If you had had more time — the if-clause
you would have finished this project — the main clause
2. When the if-clause comes before the main clause, they are separated with a comma.
If you had had more time, you would have finished this project.
3. When the main clause comes before the if-clause, they are not separated with a comma.
You would have finished this project if you had had more time.
4. In interrogative sentences, the main clause is formed like a question and the if-clause is formed like an affirmative sentence.
Would you have finished this project, if you had had more time?
(NOT: Would you have finished this project, if had you had more time?)
If you had had more time, would you have finished this project?
(NOT: If had you had hard, would you pass the exam?)
Svarīgi!
5. We do not use “when” instead of “if” in the third conditional sentences.