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.