1、用途不同。could用作助动词can的过去式,可以用于疑问句中表示现在的能力,或用于特殊疑问句中表达惊讶、迷惑等感情色彩;would用作情态动词will的过去式,用于陈述语气时表示过去的意志、决心、习惯或反复性的动作,或用于虚拟语气中表达与过去事实相反的情况。
2、侧重点不同。could更加侧重于礼貌和能力;would侧重于询问或表达意愿。
1、He said he would be here at eight o'clock.
他说他将在八点钟到达这里。
2、I would very much like to see you again.
我很想再见到你。
3、Take this to the bank for me, would you?
请替我把这送到银行去好吗?
1、We could hear sounds of revelry from next door.
我们能够听到隔壁纵饮狂欢的声音。
2、She confounded her critics and proved she could do the job.
她驳倒了批评者的看法,证明自己能够胜任那项工作。
3、Well, you can't have it, so there!
好啦,不给你了,就是这样!