could

1. MODAL You use could to indicate that someone had the ability to do something. You use could not or couldn't to say that someone was unable to do something. 能; 会

I could see that something was terribly wrong. 我能看出有很大麻烦了。

When I left school at 16, I couldn't read or write. 我16岁离开学校时不会读也不会写。

2. MODAL You use could to indicate that something sometimes happened. 可能会

Though he had a temper and could be nasty, it never lasted. 尽管他有脾气，可能会粗暴，但从来不会持续很久。

3. MODAL You use could have to indicate that something was a possibility in the past, although it did not actually happen. 本可能

He could have made a fortune as a lawyer. 他本可能当律师挣大钱。

You could have been killed!

你本可能被杀了。

4. MODAL You use could to indicate that something is possibly true, or that it may possibly happen. 可能

Doctors told him the disease could have been caused by years of working in smoky clubs. 医生们告诉他，他的病可能是多年在烟雾弥漫的俱乐部工作所引起的。

An improvement in living standards could be years away. 生活水平的提高可能还要几年。

5. MODAL You use could not or couldn't to indicate that it is not possible that something is true. 可能 (与否定词)(not)(连用，表示不可能)

They argued all the time and thought it couldn't be good for the baby. 他们一直在争论，认为这不可能对孩子有好处。

Anne couldn't be expected to understand the situation. 别指望安妮会理解这种形势。

6. MODAL You use could to talk about a possibility, ability, or opportunity that depends on other conditions. 能; 可能

Their hope was that a new and better East Germany could be born. 他们的希望是一个全新更好的东德能诞生。

7. MODAL You use could when you are saying that one thing or situation resembles another. 像

The charming characters she draws look like they could have walked out of the 1920s. 她画的那些可爱人物看上去像是从20世纪20年代走出来的。

8. MODAL You use could, or couldn't in questions, when you are making offers and suggestions. 可以 (用于建议)

I could call the local doctor. 我可以给当地医生打电话。

You could look for a career abroad where environmental jobs are better paid and more secure. 你可以在国外找份工作，那里环保工作薪水更高，也更稳定。

Couldn't we call a special meeting?

我们不能召开一次特别会议吗？

9. MODAL You use could in questions when you are making a polite request or asking for permission to do something. Speakers sometimes use couldn't instead of "could" to show that they realize that their request may be refused. 可以[礼貌]

Could I stay tonight?

今晚我可以待在这吗？

He asked if he could have a cup of coffee. 他问是否可以喝一杯咖啡。

Couldn't I watch you do it?

我不可以看着你做这件事吗？

10. MODAL You use could to say emphatically that someone ought to do the thing mentioned, especially when you are annoyed because they have not done it. You use why couldn't in questions to express your surprise or annoyance that someone has not done something. 本可以 (对某人未做某事表示恼怒)[强调]

We've come to see you, so you could at least stand and greet us properly. 我们来是为了看你，因此你至少可以站起来适当地欢迎我们。

Why couldn't she have said something?

为什么她不能说点什么呢？

11. MODAL You use could when you are expressing strong feelings about something by saying that you feel as if you want to do the thing mentioned, although you do not do it. 表示嘴上说要做实际上没有做[强调]

I could kill you! I swear I could!

我要杀了你！我发誓我要。

"Welcome back" was all they said. I could have kissed them!

“欢迎回来，”他们只说了这一句。我本想亲吻他们的。

12. MODAL You use could after "if" when talking about something that you do not have the ability or opportunity to do, but which you are imagining in order to consider what the likely consequences might be. 能 (与)(if)(连用，表示假设)

If I could afford it, I'd have four television sets. 要是我买得起，我要有4台电视机。

13. MODAL You use could not or couldn't with comparatives to emphasize that someone or something has as much as is possible of a particular quality. For example, if you say "I couldn't be happier," you mean that you are extremely happy. 不可能再 (表示已达到极致)[强调]

The rest of the players are great and I couldn't be happier. 其他运动员都很优秀，我再高兴不过了。

14. MODAL In speech, you use how could in questions to emphasize that you feel strongly about something bad that has happened. 怎么能; 怎么会[强调]

How could you allow him to do something like that?

你怎么能允许他做那样的事情？

How could I have been so stupid?

我怎么会这么傻？

15. could do with→see do