English Grammar Course for Beginners – Should Have, Could Have, Would Have

Have you ever looked back on something and thought, “I wish I had done that differently”? English has three very useful expressions for talking about the past in this way: should have, could have and would have.

They look similar, and many learners mix them up. In this lesson, you’ll learn what each one means, how to build them, how to avoid the most common mistakes, and how to use them naturally in conversation.

Lesson Overview

By the end of this lesson, you will be able to:

1. Build sentences with should have, could have and would have
2. Understand the difference in meaning between them
3. Make negatives and questions
4. Use the short forms that native speakers use
5. Avoid the most common beginner mistakes

Part 1: The Basic Formula

All three expressions follow the same simple pattern:

Subject + should / could / would + have + past participle

Subject	Modal	have	Past participle	Rest of sentence
I	should	have	studied	harder.
She	could	have	called	me.
We	would	have	helped	you.

Important rules:

• Have never changes. It is always have, never has or had, even with he, she or it.
  • She should have gone.
  • She should has gone.
• After have, always use the past participle (the third form of the verb), not the simple past.
  • I should have gone.
  • I should have went.

Quick Reminder: Past Participles

Regular verbs add -ed: work → worked, call → called, study → studied.

Irregular verbs must be learned. Here are some common ones:

Base verb	Simple past	Past participle
go	went	gone
eat	ate	eaten
see	saw	seen
take	took	taken
write	wrote	written
buy	bought	bought
tell	told	told
be	was / were	been
do	did	done
know	knew	known

Part 2: SHOULD HAVE (Regret and Advice About the Past)

Meaning

Use should have when something was the right or best thing to do, but it didn’t happen. It often expresses regret or criticism.

Think of it as: “It was a good idea, but I (or you) didn’t do it.”

Examples

• I should have brought an umbrella. (I didn’t bring one, and now I’m wet.)
• You should have told me about the meeting. (You didn’t tell me.)
• We should have left earlier. (We left late and missed the bus.)

The Negative: SHOULDN’T HAVE

Use shouldn’t have when someone did something that was a bad idea.

• I shouldn’t have eaten so much. (I ate too much, and now I feel sick.)
• He shouldn’t have shouted at his friend. (He shouted, and it was wrong.)

A Polite Use

People also say “You shouldn’t have!” when someone gives them a gift. It’s a warm way of saying, “Thank you, that’s so kind. You didn’t need to do that.”

Part 3: COULD HAVE (Possibility and Ability in the Past)

Meaning

Could have has two main uses.

1. Something was possible, but it didn’t happen.
Think of it as: “There was a chance or an option, but it didn’t happen.”

• I could have become a doctor, but I chose teaching.
• We could have taken a taxi, but we decided to walk.
• You could have asked me for help! (You had the option, but you didn’t ask.)

2. A guess about something in the past.

• “Where’s my phone?” “You could have left it in the car.” (Maybe, I’m not sure.)
• She’s late. She could have missed the bus.

The Negative: COULDN’T HAVE

Couldn’t have means something was impossible in the past.

• I couldn’t have finished the project without your help. (It was impossible without you.)
• He couldn’t have stolen the money. He was with me all day. (It’s impossible that he did it.)

A Useful Expression

“It could have been worse!” We say this to show that a bad situation wasn’t as bad as it might have been.

Part 4: WOULD HAVE (Imagining a Different Past)

Meaning

Would have is used to imagine a past situation that did not happen, and what the result would have been. It often appears with if.

Think of it as: “In a different past, this is what would have happened.”

Examples

• If I had known you were in town, I would have visited you. (I didn’t know, so I didn’t visit.)
• If it hadn’t rained, we would have played football. (It rained, so we didn’t play.)
• She would have come to the party, but she was ill. (She didn’t come.)

Willingness in the Past

Would have can also show that you were willing to do something, but you didn’t get the chance.

• I would have helped you move house. Why didn’t you ask me?

The Negative: WOULDN’T HAVE

• If you hadn’t reminded me, I wouldn’t have remembered her birthday. (You reminded me, so I remembered.)
• I wouldn’t have bought that car. It’s too expensive. (That’s my opinion about your choice.)

The Third Conditional

Would have is a key part of what grammar books call the third conditional. It follows this pattern:

If + had + past participle, … would have + past participle

If clause (the imagined past)	Result
If I had studied harder,	I would have passed the exam.
If she had left on time,	she wouldn’t have missed the train.
If we had saved money,	we could have bought a house.

Notice the last example uses could have in the result. You can also use could have (possible result) or might have (uncertain result) in third conditional sentences.

Don’t use would have in the if part of the sentence.

• If I had known, I would have called.
• If I would have known, I would have called.

Part 5: Side-by-Side Comparison

Let’s look at one situation using all three:

Situation: Ama missed her flight because she left home late.

Sentence	What it means
She should have left home earlier.	Leaving earlier was the right thing to do. (Regret or advice)
She could have taken an earlier taxi.	That option was possible. (Possibility)
If she had left earlier, she would have caught her flight.	Imagining a different result. (Imagined past)

Quick Summary Table

Expression	Main idea	Example
should have	It was the right thing, but it didn’t happen	I should have called you.
shouldn’t have	It happened, but it was a bad idea	I shouldn’t have said that.
could have	It was possible, but it didn’t happen / maybe it happened	We could have won.
couldn’t have	It was impossible	I couldn’t have done it alone.
would have	Imagined result in a different past	I would have come if I’d known.
wouldn’t have	Imagined result: it would not have happened	She wouldn’t have agreed.

Part 6: Questions

To make a question, put the modal before the subject:

Should / Could / Would + subject + have + past participle?

• Should I have called her first?
• Could they have forgotten about the meeting?
• Would you have accepted the job?
• What would you have done in my situation?

Part 7: Short Forms (Contractions)

In everyday speech, native speakers almost always use contractions:

Full form	Short form	Negative short form
should have	should’ve	shouldn’t have / shouldn’t’ve
could have	could’ve	couldn’t have / couldn’t’ve
would have	would’ve	wouldn’t have / wouldn’t’ve

Pronunciation tip: should’ve, could’ve and would’ve sound like “shud-uv,” “kud-uv” and “wud-uv.” In fast speech, have becomes a very weak “uv” or even just “a”: “I shoulda known!”

Part 8: The Most Common Mistake: “Should OF”

Because should’ve sounds like “should of,” many people (even native speakers!) write it incorrectly.

• I should of called you.
• We could of won.
• She would of helped.
• I should have called you. / I should’ve called you.

Remember: it is ALWAYS have, never of. The word of is a preposition, and it cannot follow a modal verb.

Other Common Mistakes

Incorrect	Correct	Why
I should have went home.	I should have gone home.	Use the past participle.
He could has called.	He could have called.	Have never changes.
If I would have known, I’d have come.	If I had known, I’d have come.	Use had in the if clause.
I should had listened.	I should have listened.	Always have, not had.
She would have came.	She would have come.	Come is the past participle.

Part 9: Practice Exercises

Exercise A: Choose the correct option

1. I’m so tired. I __________ gone to bed earlier. (should have / would have)
2. If you had asked me, I __________ helped you. (should have / would have)
3. We __________ taken the bus, but we preferred to walk. (could have / shouldn’t have)
4. You __________ eaten all the cake! There’s nothing left for me. (shouldn’t have / couldn’t have)
5. He __________ been at the party. He was in Kumasi that night. (couldn’t have / wouldn’t have)

Exercise B: Complete with the correct past participle

1. I should have __________ (study) more for the test.
2. She could have __________ (take) a later train.
3. They would have __________ (come) if they had been free.
4. You shouldn’t have __________ (tell) him the secret.
5. We could have __________ (buy) the tickets online.

Exercise C: Correct the mistakes

1. I should of listened to my mother.
2. She could have went to university.
3. If I would have seen you, I would have said hello.
4. He would has helped you.

Exercise D: Your turn

Write three sentences about your own life:

1. One thing you should have done last year
2. One thing you could have done differently
3. One thing you would have done if you had had more time or money

Answer Key

Exercise A: 1. should have 2. would have 3. could have 4. shouldn’t have 5. couldn’t have

Exercise B: 1. studied 2. taken 3. come 4. told 5. bought

Exercise C:

1. I should have listened to my mother.
2. She could have gone to university.
3. If I had seen you, I would have said hello.
4. He would have helped you.

Exercise D: Answers will vary. Example: “I should have saved more money. I could have learned to drive. If I had had more time, I would have travelled to Zanzibar.”

Final Tips for Mastering These Expressions

1. Remember the formula. Modal + have + past participle. It never changes.
2. Think about meaning. Should = right thing. Could = possible. Would = imagined result.
3. Say them out loud. Practise the contractions: should’ve, could’ve, would’ve.
4. Never write “of.” Always have.
5. Use them in real life. Next time something goes wrong, try describing it: “I should’ve checked the time!”

Mastering these three expressions will make your English sound much more natural, because native speakers use them every day to talk about regrets, possibilities and “what if” moments.