If he had forgotten his ticket, they wouldn't have let him in.
If she'd passed her exams, she would have gone to the university.
If the weather had been fine last weekend we would have gone to the beach.
Все предложения относятся к условным предложениям третьего типа ( Conditional III) : в главной части глагол употребляется в would+ have+ глагол в третьей форме/ или окончание ed, в придаточной части глагол употребляется в Past Perfect.