Can vs Could: What Is the Difference?

What is the difference between these examples below?

• I can speak Spanish.

• I could speak Spanish.
  

• Can you please pass the salt?

• Could you please pass the salt?
  

• You can get injured doing that.

• You could get injured doing that.

If you don't know, keep reading to find out more!

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Introduction

• Can and could are modal verbs used to talk about ability, possibility, and used when asking for a favor or request.
  

• Can is used for present ability.

• Can is used when there is a higher probability of an action or event happening in the future.

• Can is used in requests or when asking for a favor.
  

• Could is used for past ability.

• Could is used when an action or event that has around a 50% chance of happening.

• Could is used in requests when asking for a favor.

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Present Ability vs Past Ability

In regards to the examples above, can is used for present abilities, while could is used for past abilities. You can think of could as the past tense of can.

• I can speak Spanish.

  • I am able to speak Spanish now, in the present moment.

• I could speak Spanish.

  • I am not able to speak Spanish now, but I was able to speak Spanish in the past.

Now, here are a few more examples.

1. Present ability (can):

   1. I can speak Spanish fluently now after years of practice.

2. Past ability (could):

   1. When I was younger, I could run much faster than I can now.

3. Present ability (can):

   1. With my new glasses, I can see the small print clearly.

4. Past ability (could):

   1. Before the accident, I could play the piano beautifully, but now I struggle with it.

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Requests

We can use can and could in requests or when asking for a favor. When we use can and could, is there a difference, and if so, what is it? Well, yes there is a difference actually. Although it is a small difference, could is considered to be more polite than can.

1. Using "can" for a request:

   1. Can you pass me the salt, please?

2. Using "could" for a polite request:

   1. Could you please help me with this heavy box?

3. Using "can" for a direct request:

   1. Can you email me the report by tomorrow morning?

4. Using "could" for a more tentative or polite request:

   1. Could you possibly lend me your umbrella for today?

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Possibility

When can and could are used to refer to possibility. Can refers to an action or event that is certain or likely to happen. Could is used to refer to an action or event that might happen.

1. Using "can" for general possibility:

   1. It can get quite cold in the mountains during the winter.

2. Using "could" for a hypothetical or less certain possibility:

   1. If you hurry, you could catch the last train home.

3. Using "can" for a strong possibility:

   1. With hard work, you can achieve your goals.

4. Using "could" for a more speculative or conditional possibility:

   1. There could be a chance of rain later this afternoon.

5. Using "can" for expressing capability as a possibility:

   1. He can swim across the lake if he trains regularly.