A2 · 情态动词
can、could 和 be able to
同样三个词，表达三件不同的事。
一目了然
- 记住这句
- 长期会：could。那一次做成了：was able to。
- 构成
- I can drive.能力
- 标志词
- can
- could
- be able to
- manage to
- 易错点
- 错误：After an hour I could finally start the car.正确：After an hour I was finally able to start the car.
轮到你了
本主题共有 5 道练习。答案在浏览器里直接判断，不会离开你的设备。
构成形式
形式是怎样构成的
每一行先给出意思，再给出英语的形式。颜色标出的是各个形式之间变化的部分。
词干（不规则）
| 能力 | I can drive. |
| 我会做饭 | I can cook |
| 你会做饭 | you can cook |
| 他、她、它会做饭 | he, she, it can cook |
| 我们会做饭 | we can cook |
| 你们会做饭 | you can cook |
| 他们会做饭 | they can cook |
| 过去的长期能力 | I could drive at eighteen. |
| 我（以前）会做饭 | I could cook |
| 你（以前）会做饭 | you could cook |
| 他、她、它（以前）会做饭 | he, she, it could cook |
| 我们（以前）会做饭 | we could cook |
| 你们（以前）会做饭 | you could cook |
| 他们（以前）会做饭 | they could cook |
| 过去的一次成功 | I was able to fix it. |
| 我（那次）帮上了忙 | I was able to help |
| 你（那次）帮上了忙 | you were able to help |
| 他、她、它（那次）帮上了忙 | he, she, it was able to help |
| 我们（那次）帮上了忙 | we were able to help |
| 你们（那次）帮上了忙 | you were able to help |
| 他们（那次）帮上了忙 | they were able to help |
| 将来 | I will be able to drive next year. |
| 礼貌的请求 | Could you pass the salt? |
规则逐条讲
这个主题讲的形式提示要用这个形式的词
过去某一次成功做到的事，用 was able to，不用 could。
The door was stuck, but she was able to open it.门卡住了，但她还是把它打开了。
否定时，couldn’t 也可以用于单次的事。
I could not open the door.我没能把门打开。
需要第二个情态动词的地方，用 be able to 代替。
She might be able to come.她也许能来。
与感官动词连用时用 can，相当于中文的“看得见”“听得到”。
I can see the sea from here.从这儿我能看见大海。
例句
Can I have the bill, please?请给我结一下账，好吗？
He could read before he started school.他上学前就会认字了。
We were not able to reach them.我们没能联系上他们。
You can leave your coat here.您可以把外套放在这儿。
再看 6 个例句
Can you hear me?你听得见我说话吗？
I could not find the address.我没找到那个地址。
Could you say that again, please?您能再说一遍吗？
She was able to fix it herself.她自己把它修好了。
We can meet on Friday if you like.你愿意的话，我们可以星期五见面。
He could play the piano at six.他六岁就会弹钢琴了。
中文母语者最容易踩的坑
注意
中文的“能”既可以说一直具备的能力，也可以说某一次的成功：“过了一个小时，车终于能发动了。”学习者因此把所有过去的“能”都译成 could。可是在英语里，Yesterday I could finally talk to her 听起来像是“当时有机会”，而不是“真的谈成了”。某一次真正做成的事，要用 was able to 或 managed to。
详细讲解
阅读全文 · 约 1 分钟
can 有三种意思，正好对应中文的三个词：学会的本领，就像“会”——I can swim（我会游泳）；条件上的可能，就像“能”——You can pay by card（可以刷卡）；日常口语中的许可，就像“可以”——You can go now（你现在可以走了）。中文分三个词说，英语一个 can 全包了。
could 是 can 的过去式——但只用于长期具备的能力。过去某一次成功做到的事，要用 was able to 或 managed to。When I was ten I could ride a horse（我十岁时就会骑马）是对的；但说那天总算赶上了火车，就要说 I was able to catch the train。中文“终于能……了”“总算……成了”在这里很容易误译成 could。
could 也是现在时的礼貌说法：Could you help me? 比 Can you help me? 客气得多。
这个主题你掌握得怎么样？
练习之后这里会自动填写。你也可以随时在这里自己修改。