would和could的区别在哪里?

would和could的区别在哪里? 怎么用would和could啊?它们的区别在哪里啊? would和could的区别 should ,would ,might ,could 在用法上的区别在哪里 could you和would you的区别 英语：Could和Would的用法有什么区别? can,could和will,would的用法以及区别 would you mind和could you please的区别 can和could,should,would等词语的用法区别? could have done和would have done的区别 情态动词would与could的区别是什么?在表示委婉的请求时,好象意思都差不多.如：Would you like to try it?和Could you show me another blue dress?这两个句子当然不能互换,但这区别在哪里呢?能简单地说清楚 Could you和would 什么区别? 请问should,could,would的分别和用法?这个三个词是shall,can,will的过去式吧?（sorry,英语不是很好-_-|||)它们的区别在哪里?还有用法又是怎样呢? 请问could和would在虚拟语气中有什么区别?请问could和would在虚拟语气中有什么区别. can 、would 、could 、need的区别 would和could之间的区别?表示委婉语气时的区别是什么? would、should、could和might的区别我想问下,这四个有什么区别. used to 与would 的区别在哪里