Here in Korea, a lot of public educations are not in a great state. People have been educated too simply that the past "Tense" of Can is Could. But they never learned or been told deeply, so they get frustrated when they confront something like "I could get up early yesterday".

Recently, some ideas like "Could is not the past form of Can at all, and we were all taught wrongly" have spread really quick. And now people wouldn't listen to that the word "Past form" could mean hypothetical, politeness, etc other than Tense itself. They have already turned away and believe that Could has nothing to do with Can now.

If I show them like "Look, the dictionary, the natives would look up, shows that Could is the past form of Can at the first entry" and all I got is "Oh come on, that's all the grammar stuff you know. In REAL English, It's not like that~".

I know I'm asking too much and the subject is somewhat a bit off to this website but any ideas to help them? (actually me).

  • 1
    I agree with Tasneem.. they should converse with a native speaker and ask. I would like to know, if they have moved on from believing that the past form of can is could, then what they think the meaning of could is, have you asked them ? And source of their perception ?
    – Spectra
    Commented Jan 24, 2019 at 13:49
  • You're essentially presupposing a conclusion, then asking how that conclusion might be reached. Back up and take a more neutral approach. There are two different analyses here: ① could is a form of can, or ② could is not a form of can. What are the implications of each analysis, and what data can we find that supports one conclusion or the other? Once you know that, you can move on to decide what the answer is – not before.
    – user230
    Commented Jan 24, 2019 at 18:26

1 Answer 1


You are right that "could" is used as the past tense of "can". The likely reason for the confusion among your peers is that "can" is a modal verb; that is an auxiliary verb that indicates necessity or possibility. It is not the same as most other verbs which are modified to indicate a current, past, or future action.


Consider the verb to run:

The past tense is ran.

So you might say:
"John can run in this afternoon's race".

This means that John is allowed, or that John is able to run in the near future.

But after the race was over you would say:

John ran.

You would not say:

John could run.

In fact, this would still refer to a future possibility of John running.

In most situations when you say that you can do something in the future, you do it! So after the fact you would be saying that you did it, not using "could" to indicate a possibility.

Your example of "I could get up early yesterday" is wrong. Presumably this is meant to be the past tense of "I can get up early tomorrow". Well, if you did get up early then you would say "I got up early yesterday".

"Could" only becomes the past tense of "can" when speaking about a possibility in the past, for example:

When I was younger I could run.

This is not referring to a specific instance of running, but speaking generally and saying that you were able to run.

Going back to your example about getting up, if you had an opportunity to get up early the previous day but you did not take that opportunity then you might say "I could have got up early yesterday".

I can see how this could be difficult for non-native English speakers if you are used to changing the tense of a sentence simply by modifying a single verb. There are fewer situations where "can" is substituted with "could" than with other verbs.

  • In the example that you gave, suppose, the race is over and John didn't run, but you wish he had run, then what do you say ? John could have run (like in conversations)?
    – Spectra
    Commented Jan 24, 2019 at 15:27
  • @Spectra That's right. I cover that in the penultimate paragraph. Although you could also say "John could have run" to mean he might have but you are unaware.
    – Astralbee
    Commented Jan 24, 2019 at 15:59
  • ohh yeah, that is another possibility !!
    – Spectra
    Commented Jan 24, 2019 at 17:57
  • Well, thanks for the answer. So I used your answer to one of them whom I already had told about Could for the past general abilities. Now he's counterattacking me like "See? this answer doesn't match what you mentioned before. If you can't use Could for the past action because it's something already done, why there're exceptions like "I could hear, I could see"? This only shows that grammar is just grammar". They are just full of distrust against grammar itself. I'm so frustrated that the video saying Could is not related with Can has almost reached over 1.2M view, and people love it.
    – dolco
    Commented Jan 25, 2019 at 0:35
  • @dolco Those aren't exceptions! If you did see something then you would say "I saw" as the true past tense. When people say "I could see" they are not putting an action in the past but using the modal verb to say that they were able to see, or that it was possible for them to see.
    – Astralbee
    Commented Jan 25, 2019 at 8:45

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