我不可能是你,即“If I am you”不可能是事实,所以是错误的,只能说 If I were you。
与现在事实相反的虚拟,if从句用过去式,主句用主语+should / would / could / might,这是虚拟语气的时态倒退。比如:
If I were you, I would reconsider their advice.
假如这句话是事实的话是:If I am you, I will reconsider their advice.
以上这个我明白。
但为什么如果这句话是事实的话不能这样说:
If I am you, I would reconsider their advice?
would不是will更加委婉的用法吗?那这句话的时态倒退是怎样的,would本身是will的过去式,但它作为和will意思有差别的情态动词时有过去式吗?