虚拟语气

wish

wish 可用于虚拟语气

• I wish that we were together.
  我希望我们依然还在一起（暗指我们已经分手了。）

wish 也有普通的用法 wish to do = want to do

• I wish to buy a car.
  我希望我能买一辆车。

if

当if使用虚拟语气时，前后语态将都会成为虚拟。
If I were a boy ,I think I could understand.
假如我是男孩,我想我会明白。

would rather

would rather 的意思是情愿去做... 有would rather to do sth 的结构
当would rather 用于虚拟语气的时候，美式和英式的用法会不一样。
英式 would rather that did 均可以表达现在时和未来时。
美式：would rather that do 表示未来时,would rather did 表示现在时
两者均用had did 表示过去时。