3.過去式助動詞 + 原形V
主詞 + should/would/could/might + 原形V
If he were rich, he would buy the bank.
If I had time, I would study French.
If I could fly, I would fly to London.
If I were a bird,......
If you were here,......
If he were rich,......
主詞 + should/would/could/might + have +p.p.
If he had studied hard, he could have won the scholarship.
If I had had enough time, I would have gone abroad with you.
主詞＋ should, would/ could, might ＋原形V
If the sun were to rise in the west, I would not change my mind.
2. If I were to be reborn, I would be a musician.