来人啊

虚拟语气我只记住一句话 如果我有刀 我立刻杀了你 如果你真的挂了 那我就惨了 警察会找上门来 但是我用英文说的话 if I had knife,I would kill you right now. 那我就肯定没事

had I been you 是 if I had been you 的减省倒装形式，意思一样。句意是：如果当时我是你，我应该已经安顿下来了。主句、从句都是对过去虚拟，所以使用过去完成时。

Had I been you, I could have settled down. -> 当时我是你的话, 我有机会可以安顿下来
If I were you, I would have already settled down. -> 如果我是你，我就已经安顿下来了

对的