例：If I knew it, I would tell you!
例：If you had called me yesterday, I would have bought it for you!（如果你昨天有打電話給我的話，我就已幫你買了!）
例：If you had called me yesterday, I would be ready now. （如果你昨天有打給我，現在我就有所準備了）
If I , I travel the world.
If I know you, I be here with you.
If you hardly, it be you standing here.
If you it yesterday, she away.
What you do if you me?
1.could, afford, would, around
3.had studied, would
4.had said, wouldn't have gone