来自：查字典高考网 2017-03-04
Can和Could 都是情态动词。一般情况下，Could比Can 更礼貌（或者更正式）一些。下面分别来介绍 Can和Could的一些用法。
CAN
The three main uses of Can are: 1) ability 2) possibility and 3) permission. However there are some other uses of Can as we will see below.
1. To express ability
Can means to be (physically) able to do something OR to know how to do something.
I can speak two languages.
2. To express a possibility (in general)
This refers to a theoretical possibility.
Note: we don't use can to talk about future possibilities. For this you would use may or might.
I know you can win the competition.
3. To offer to do something for others
Can is used when you offer to help someone or to do something for them.
You don't need to walk home. I can take you there if you like.
4. To ask for or give permission / To request something
Can is used to ask for / request permission or to give permission.
Note: Can't is used to refuse permission.
Can means to be (physically) able to do something OR to know how to do something.
Mary, you can play outside if you like.
5. Can't: Something that is forbidden or not allowed
You can drive as fast as you want on the German motorways.
COULD
Could is similar to Can and often replaces Can in the past tense (though not always)
1. To express ability in the past
She could juggle eight balls when she was only 10 years old.
2. Polite word used to ask for permission or to request something (in the present)
Could I please use your bathroom?
3. General permission in the past
He couldn't go to the concert because his mother wouldn't let him.
4. Couldn't: Sure that something is untrue
Just like can't, you can use couldn't when you are sure that something isn't true or real.
He couldn't have painted that. He has no artistic ability at all.
5.Could: A conditional form ofCan
Would + Can = Could. Note: Would be able to can replace could in the following examples.
I could write the letter if you told me what to include.
【情态动词中Can和Could有怎样的区别】相关文章：
★ 高考英语词组give off与 give out辨析区别
探秘历史 第二季 第479集 河南叛逆高考生，写下8000字批判作文，现状如何？
创艺第二届：2019届高考录取表彰大会暨“核桃音乐节”合影——你只管努力，剩下的交给创艺
学渣儿子高考，英语选择题全选B！老师通报成绩的那一刻父亲懵了
张雪峰高考志愿填报指南 第47集 高考志愿，令人头疼的数学系，才是专业万金油，毕业后机会多
沈阳音乐学院郎亦农教授的女高音高考曲目解析课程 第1集 沈阳音乐学院郎亦农为你讲解女高音高考曲目
你高考成绩高吗？这道题目怎能成立？高难度奥数，能不能把你难住
张雪峰高考志愿填报指南 第15集 高考填报志愿，想学电子信息类专业，推荐报这六所高校，不出错
