could have done sth

could have done sth
1. (indicating past ability) 可以；能；会
- In those days you could get a job easily. 在那个年代人们可以轻松地找到工作。
- I couldn't sleep because of the noise. 噪声让我无法入睡。
- They couldn't understand a word. 他们一个字也听不懂。
2. (might at times) 可能会；有时会
- He could be very pleasant when he wanted to be. 他想要友好的时候会非常友好。
3. could have done sth
(indicating what did not happen) 本可以
- He could have made a fortune as a lawyer. 他本可以当律师挣大钱的。
- You could have been killed! 你差点就没命了！
4. (indicating what is possible) (表示可能性)可能
- You could be right. 你可能是对的。
- He could be in the library. 他大概在图书馆。
- They could have forgotten. 他们可能忘记了。
- She could have been delayed. 她可能被耽搁了。
- An improvement in living standards could be years away. 可能多年之后生活水平才能得到提高。
5. (indicating what is not possible) (用于否定句, 表示某事不属实)可能
- Anne couldn't be expected to understand the situation. 别指望安妮能弄明白当前情势。
- He couldn't have been more than fourteen years old. 他不可能超过十四岁。
6. (might under certain circumstances) (表示可能性、机会或能力)可能
- Their hope was that a new democracy could be born. 他们的希望是新的民主国家能够诞生。
7. (in suggestions) (表示建议)可以
- I could always call the local doctor. 我随时可以给当地医生打电话。
- It's boring to walk all alone.—Couldn't you go for walks with your friends? 一个人走路很没意思。——你可以和朋友们一起去散步呀？
8. (in requests) (用于礼貌地提出请求或征得许可)能, 可以
- Could I speak to you in private? 我可以跟你单独谈谈吗？
- He asked if he could make a phone call. 他问是否可以打个电话。
9. if I could…<口,正式> (interrupting someone) (用于礼貌地打断别人或引出将要说的话)请允许我…
- Now, Dave, if I could just interrupt. 那么, 戴夫, 抱歉打断一下。
could I …
(interrupting someone) (用于打断别人)请允许我…
- Could I stop you there? 我能打断您一下吗？
(introducing a topic) (用于引入新话题)请允许我…
- First of all, could I begin with an apology? 首先, 请允许我表示歉意。
10. (expressing annoyance) (用以强调某人应该做所提及的事情)应该
- You could at least say hello! 你至少该打个招呼！
11. (emphasizing strong feelings) (强调想要做某事的强烈感情)
- She could have screamed with frustration. 她失望得差点儿叫出来。
12. (in conditional clauses) (用在if后以谈论没有能力或机会做但为考虑可能的结果而设想去做的事)
- If I could afford it I'd have four television sets. 如果我买得起, 我就想要四台电视机。
- If only I could get some sleep, I would be able to cope. 要是能睡上一会儿, 我就能应付了。
13. (with comparatives) (与比较级连用, 强调某人或某物具备某种特征的程度)太…, 再…不过
- I couldn't be happier. 我简直太开心了。
- The news couldn't have come at a better time. 这消息来得正是时候。
See: could

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