Structure
If-clause:
Past Perfect
Main-clause
would (could/might) have + participle
If he hadn't helped me, .....
I would have been late if ......
If he hadn't lied to her, .....
She would have believed him if....
If they had won, ......
We would have seen Harry Styles if....
If you hadn't overslept, ......
She would have passed her exams if .