这四个的区别不大,仅仅在可能性大小方面有细微的差异。
最肯定的是would (会,含有certainly的意思)
很可能的是should (应该,含有probably的意思)
次之则是could(可能,含有possibly的意思)
可能性最小的是might(也许)
例子:
I would/should/could be happy if I were king.
如果我是国王,我肯定/应该/可能很开心。【这个例子不宜用might】
另例:
If I were you, I would (should, could, might) help him.
如果我是你的话,我就会(应该,可能,或许)帮助他了。【四个都能用】
体会以下例子:
You could have done better if you had been more careful.
要是你再细心一点的话,你可能会做得更好。【这话可能是老师对学生说,could表示不是很肯定】
I would have done better if I had been given more time.
要是时间再多一点的话,我就会做得更好。【这句则很可能是学生对老师说,would透露出自信】