The teacher said to his best friend “ if I were you, I would be patient in this situation
⇒The teacher advised his best friend to be patient in that situation (advise sb to V: khuyên ai làm gì)
⇒The teacher said to his best friend if he had been her, he would have been patient in that situation (lùi thì câu điều kiện loại 2->loại 3)