🧭 Grammar · Modal Verbs
Should Have, Could Have & Would Have
Look back at the past and say what was the wrong choice, what was possible but never happened, and what would have happened if things had gone differently.
Grammar › Modal Verbs › Should Have, Could Have & Would Have
The rule in one sentenceUse should have to judge a past choice as right or wrong, could have for a past possibility or ability that never actually happened, and would have for the imagined result of a past that never occurred.
What’s the difference?
All three build the same way — modal + have + past participle — but they answer three completely different questions about the past: was it the right decision, was it possible, and what would have followed if things had gone another way?
Should have judges a real, finished action against a better alternative that didn’t happen: First Reformed shouldn’t have kept its ending quite so ambiguous, some viewers felt; many others found the uncertainty was the whole point. It’s regret or criticism aimed at a choice that was actually made.
Could have talks about something that was genuinely possible at the time but simply didn’t happen: Peter Bogdanovich could have shot The Last Picture Show entirely in colour, but he deliberately switched to black-and-white to evoke 1950s Texas. The option existed; it was never taken.
🎬 Compare: “First Reformed shouldn’t have ended so abruptly” (a judgement on the decision that was made) vs. “First Reformed could have offered a clearer resolution instead” (an option that existed but was never used) vs. “If First Reformed had offered a clearer resolution, the film would have felt far less unsettling” (the imagined result of that unused option).
Should have criticises, could have names the road not taken, would have imagines where that road led.
Would have completes a hypothetical past — it’s the imagined consequence of an if-clause that never came true: If Anthony Hopkins hadn’t taken the role, another actor would have played Hannibal Lecter in The Silence of the Lambs, and audiences would have missed his Oscar-winning performance.
How to build it
Should have — the right/wrong choice
The Academy should have given Do the Right Thing a Best Picture nomination, many critics argued at the time.
First Reformed shouldn’t have left its ending so open to interpretation, a few reviewers argued.
shouldn’t have + past participleShould Marvel have given Eternals a longer runtime to develop each character?
Should + subject + have + past participleCould have — an unused possibility
Peter Bogdanovich could have shot The Last Picture Show entirely in colour.
Without practical effects, the creature in The Thing couldn’t have felt as terrifying as it did on screen.
Could Jackie Chan have used a stunt double for the fight scene in Police Story, but chose not to?
Could + subject + have + past participleWould have — the hypothetical result
If Anthony Hopkins hadn’t taken the role, another actor would have played Hannibal Lecter in The Silence of the Lambs.
If Robert Zemeckis hadn’t waited for motion-capture technology to mature, The Polar Express wouldn’t have looked so visually groundbreaking in 2004.
If a different studio had distributed it, would Green Book have still won the Best Picture Oscar?
Would + subject + have + past participleWhen to use which
Talking about mistakes & missed chances
- Judging a decision that was made: Paramount shouldn’t have delayed World War Z’s marketing so close to release.
- Naming an option that existed: Bill Condon could have released The Twilight Saga: Breaking Dawn as one film, but split it into two parts from the start.
- Regret about your own past choices: I should have watched Moonlight before it won Best Picture.
Talking about imagined outcomes
- The result of an unreal past (third conditional): If First Reformed had ended more conventionally, fans would have reacted very differently to it.
- Something implied without “if”: Without practical effects, the creature in The Thing would have looked far less convincing.
- Speculating about an alternate casting choice: Would Julia Roberts have played Vivian Ward in Pretty Woman the same way if Molly Ringwald hadn’t turned down the role?
Signal words
These phrases usually signal you’re about to look back and judge, or imagine, the past.
Visual guide
Teacher Teddy’s illustrated guide to this rule is being drawn — the full swipe-through infographic will appear here soon.
Common mistakes
❌ If Bogdanovich would have used colour throughout The Last Picture Show, the black-and-white scenes would have lost their impact.
✅ If Bogdanovich had used colour throughout The Last Picture Show, the black-and-white scenes would have lost their impact.
Never use “would have” inside the if-clause — the if-clause takes had + past participle; would have belongs in the result clause only.
❌ The Academy should have gave Do the Right Thing a Best Picture nomination.
✅ The Academy should have given Do the Right Thing a Best Picture nomination.
These modals always take the past participle (given), never the past simple form (gave).
❌ First Reformed could of used a more conventional ending.
✅ First Reformed could have used a more conventional ending.
“Could of” is a spelling mistake caused by the sound of the contraction “could’ve” — always write “have”, never “of”.
Exceptions & tricky cases
Three cases where the pattern stretches beyond the basic rule.
1. “Would have” without an explicit “if”. The hypothetical condition can be implied by context instead of stated: Without practical effects, the creature scenes in The Thing would have looked far less convincing on screen. No if-clause appears, but the counterfactual meaning is still there.
2. “Should have” can express surprise, not just regret. It’s strange that Spotlight should have won Best Picture as one of the lowest-grossing winners in decades — but Tom McCarthy’s film did exactly that. Here should have marks something remarkable that really happened, not a missed choice.
3. “Could have” and “might have” often overlap for uncertain past possibility. David Lynch could have chosen a clearer ending for Mulholland Drive and David Lynch might have chosen a clearer ending both work — could have leans slightly toward “it was possible”, might have leans slightly toward “it’s uncertain what happened”.
Practice: judge the past
Eight quick questions. Choose the form that fits — you get the explanation either way.
1. If Peter Bogdanovich ___ used colour throughout The Last Picture Show, the black-and-white scenes would have lost their impact.
The if-clause needs had + past participle — would have never appears there.
2. First Reformed ___ left its ending so ambiguous, a few critics complained — though most praised the boldness of the choice.
Judging a finished past decision needs shouldn’t have + past participle.
3. Without practical effects, the creature in The Thing ___ felt as terrifying as it did on screen.
A hypothetical past possibility needs have + past participle: couldn’t have felt.
4. If Anthony Hopkins hadn’t taken the role, another actor ___ played Hannibal Lecter in The Silence of the Lambs.
The result clause of an unreal past condition needs would have + past participle.
5. The Academy ___ given Do the Right Thing a Best Picture nomination, in the eyes of many critics.
Should have always takes the past participle (given), never the past simple (gave).
6. First Reformed ___ used a more conventional ending.
“Could of” is never correct in writing — it’s always “could have”.
7. If Robert Zemeckis hadn’t waited for motion-capture technology to mature, The Polar Express ___ looked so visually groundbreaking in 2004.
The imagined result of the unreal past condition needs wouldn’t have + past participle.
8. It’s remarkable that Spotlight ___ won Best Picture as one of the lowest-grossing winners in decades.
Should have + past participle can mark surprise at something that genuinely happened, not just regret.
Keep going
Related lessons in Modal Verbs:
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