Could Do and Could Have Done

Could Do and Could Have Done

Hello English learners! Today, we’re going to look at two very common English expressions: could do and could have done. These forms are used to talk about possibility, ability, and suggestions — both in the present/future and in the past.

Let’s dive in step by step.

“Could” as the past of “can”

Sometimes we use could as the past form of can — especially when we’re talking about ability in the past.

• I can run very fast now. (present ability)
• When I was younger, I could run much faster. (past ability)

More examples:

• When we lived by the sea, we could see the lighthouse from our window.
• I could swim when I was five years old.
• She couldn’t (could not) read when she started school.

Could Do and Could Have Done

“Could” for suggestions and possibilities

We also use could to talk about possible actions or suggestions for the present or future. It is similar to can, but sounds less certain and more polite.

A: What shall we do this weekend?

B: We could visit the countryside.

 (= It’s one possible idea.)

• If you’re bored, you could start a new hobby.
• You could take the train instead of flying.
• We could try that new Italian restaurant.

Compare:

We can go to the park → definite plan.

We could go to the park → polite or possible suggestion.

“Could” for unreal or imaginary situations

We also use could (not can) when something is not realistic or we are just imagining it.

• I’m so hungry, I could eat a horse! (exaggeration)
• It’s so peaceful here, I could stay forever.
• I could live in this town — it’s beautiful! (imagining, not real)

Compare:

I can live here → realistic and true.

I could live here → hypothetical or dreamy.

Could Do and Could Have Done

 “Could” for present or future possibility

Could can also mean something is possible now or in the future — similar to might or may.

• The story could be true, but I doubt it.
• Take an umbrella. It could rain later.
• He’s not at home. He could be at work.

Compare:

Water can freeze at 0°C. (a general fact)

The water could freeze tonight. (possible now or soon)

“Could have done” — talking about the past

Now let’s move to could have + past participle.

We use this form to talk about past possibilities — things that were possible, but didn’t actually happen.

• You could have told me you were coming! (= You didn’t tell me.)
• She could have won the competition, but she didn’t try hard enough.
• We could have taken a taxi instead of walking.
• I was so tired last night; I could have slept for ten hours.

Compare:

I could sleep for a week! → now (present feeling).

I could have slept for a week! → past (I didn’t, but it was possible).

“Couldn’t” and “couldn’t have done”

We use couldn’t for something impossible now or in general, and couldn’t have done for something impossible in the past.

• I couldn’t live without music. (= It’s not possible for me.)
• Everything is perfect. It couldn’t be better!
• We had a lovely holiday. It couldn’t have been nicer.
• He couldn’t have gone to the party; he was abroad that week.

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