Такие предложения выражают нереальные действия, которые относятся к 1) настоящему или будущему времени. Схема такого предложения следующая: If+Past Simple/Past continuous+Future in the past (т.е. would)+ глагол: 2) прошедшему времени. Схема предложения: If Past Perfect, Future in the past+have+3 форма глагола (причастие II, которое у правильных глаголов совпадает с прошедшим временем. Пример (главное понять принцип, а дальше легко) -If the weather were nice, I would go to the beach.– Если бы (сейчас) была хорошая погода, я бы пошел на пляж. (но погода не хорошая, и изменить это нереально!) If I had a lot of money, I would open my own restaurant.If the weather were nice, I would go to the beach.If I had studied hard, I would have passed the exam. If it hadn’t been raining, I would have gone to the game.If I had eaten breakfast several hours ago, I would’t be hungry now. If we paid more attention to grammar, we should know the language better. I should not have been late yesterday, if my watch had been right.If she hadn't put on a short dress, she wouldn't have attracted such attention.If I had learned English before, I could have found a good job long ago. If you had seen the film, we could discuss it now.