subject + could + have + past participleUse this form to talk about a possible past action or explanation.
Modal Perfect
B1Modal Perfect uses could, should, or would + have + past participle to look back at past situations: possibility, regret, or an imagined result.
What you'll learn
- Build modal perfect with modal + have + past participle.
- Use could have for a possible past result or explanation.
- Use should have for regret, criticism, or missed advice.
- Use would have for an imagined past result.
- Choose the correct past participle after have.
- Make negative forms like couldn't have and shouldn't have.
Structure
subject + should + have + past participleUse this form for the better past action after you know the result.
subject + would + have + past participleUse this form for the result in an unreal past situation.
subject + couldn't/shouldn't/wouldn't + have + past participlePut not on the modal, then keep have + past participle.
Build a sentence
Subject
Verb
Annashouldhave called
Anna should have called Lisa.
No to after should: should have called.
When to use
Possible past
Use could have when you look back and say one past option was possible. Tom could have taken a taxi, but he decided to walk.
Regret or criticism
Use should have after you know the result and want to say the better past action. Anna should have checked the address before she left.
Imagined result
Use would have for the result in a different past situation. We would have arrived on time, but the road was closed.
Markers
yesterdaylast nightearlierthis morningbutafterwards
Spelling
go
→ gonecould have gonesee
→ seenshould have seentake
→ takenwould have takenregular verb: call
→ calledshould have calledCommon mistakes
Wrong
She should called Tom.
Correct
She should have called Tom.
Modal perfect needs have before the past participle.
Wrong
Maria should to have checked the time.
Correct
Maria should have checked the time.
After should, use have directly. Do not add to.
Wrong
He could have went home earlier.
Correct
He could have gone home earlier.
After have, use the past participle gone, not the simple past went.
Wrong
They could had won the game.
Correct
They could have won the game.
After a modal, use have, not had.
Wrong
Lisa could have not seen your email.
Correct
Lisa couldn't have seen your email.
In this pattern, not goes with the modal: couldn't have, shouldn't have, wouldn't have.
Common misconceptions
❝ If the sentence is about the past, the modal itself changes to a past form. ❞
The modal stays could, should, or would. Past time is shown by have + past participle.
❝ Should have means the action really happened. ❞
Should have often means the opposite: it was the better action, but it did not happen.
Skills in this rule (7)
COULD_HAVE_POSSIBILITYw4Use could have + past participle for a past possibility
Use could have when a past result was possible but did not happen or is only one possible explanation. It often appears when you imagine another past option.
SHOULD_HAVE_FOR_REGRETw5Use should have + past participle for regret or past advice
Use should have when you say the better action in the past. It often shows criticism, regret, or missed advice after the result is already known.
WOULD_HAVE_FOR_IMAGINED_RESULTw5Use would have + past participle for an imagined past result
Use would have for a result in an unreal past situation. It often answers What was the result in that different past situation?
MODAL_HAVE_PAST_PARTICIPLEw5Build modal perfect with modal + have + past participle
After could, should, and would, use have and then the past participle. Do not change the modal and do not use to.
PICK_PAST_PARTICIPLEw4Choose the past participle after have
After have, the verb must be a past participle, not a base form or simple past form. This matters most with irregular verbs like go → gone and see → seen.
NEGATIVE_MODAL_PERFECTw4Use negative forms like couldn't have and shouldn't have
Put not on the modal, then keep have + past participle. Use negative forms to say something was not possible or was the wrong past action.
LOOK_BACK_TO_PAST_RESULTw3Recognize markers that point to a finished past situation
Modal perfect looks back from now at an earlier finished situation. It often appears with clues like yesterday, last night, earlier, or after seeing a result now.