Should Have / Could Have / Would Have

1. Overview & Concept

• What is it? Modal perfect constructions — should have, could have, and would have + past participle — are used to talk about hypothetical or unrealised past situations: things that didn't happen but could or should have.
• Purpose: To express regret, criticism, missed opportunities, and hypothetical past results.

2. Structure & Formula

Spoken contractions: should've, could've, would've (note: never write should of / could of / would of)

3. Usage Rules

• Rule 1 — Should have: regret or criticism about the past
• The action did not happen, but it should have:
• You should have studied harder. (= but you didn't, and the result is bad)
• I should have taken that job. (= I regret not taking it)
• Negative — the action happened but shouldn't have:

• She shouldn't have told everyone. (= she did, and it was wrong)

• Rule 2 — Could have: unrealised past possibility or ability

• Something was possible but didn't happen:
• We could have taken the earlier train. (= it was possible, but we didn't)
• He could have become a doctor. (= he had the ability, but chose not to)
• Negative — something was impossible in the past:

• They couldn't have survived without help. (= it was impossible)

• Rule 3 — Would have: hypothetical past result (often in conditionals)

• Used in the result clause of third conditionals:
• If I had known, I would have come. (= but I didn't know, so I didn't come)
• She would have passed if she had revised. (= she didn't revise, so she failed)
• Also used to express past willingness or refusal:
• He would have helped, but he was busy.
• She wouldn't have agreed to that.

4. Signal Words & Context

5. Common Pitfalls

6. Real-World Examples

1. You should have told me — I would have helped!
2. We could have caught the bus if we'd left five minutes earlier.
3. I would have gone to the party, but I was ill.
4. She shouldn't have shared that confidential email.
5. He could have been a professional footballer — he was incredibly talented.
6. They would have been disappointed if we hadn't shown up.
7. I should have listened to my doctor.
8. You couldn't have done anything differently — it wasn't your fault.
9. We would have stayed longer if the weather had been better.
10. She should have double-checked the figures before the presentation.

7. Summary Table