Zorg Spaceshould have, could have, must have
The rule
Put have + the past participle after a modal and you are looking back at something that is now too late to change. I should have called regrets what you did not do. You could have told me is a mild complaint about a missed chance. She must have forgotten is a confident guess about the past, and he can’t have known is its confident opposite. might have leaves it open. In speech have is squeezed to ’ve, which is why learners write should of — it is never correct.
should / could / must / can’t / might + have + past participle
Examples
I should have booked a table.
You could have told me about the change.
She must have left her phone at work.
He can’t have seen the sign.
Common mistakes
-
Wrong: I should of asked first.
Right: I should have asked first.
of is only what ’ve sounds like; the word is have.
-
Wrong: I should have went earlier.
Right: I should have gone earlier.
After have you need the third form of the verb.
-
Wrong: She must not have got the message.
Right: She can’t have got the message.
For a confident negative guess about the past, use can’t have.
Practice questions
Try each one yourself first, then open “Show answer” for the solution and the reason.
-
1Choose the correct sentence.
- I should had taken the earlier train.
- I should have taken the earlier train.
- I should have took the earlier train.
- I should of taken the earlier train.
Show answer
Answer: B I should have taken the earlier train.
should + have + the third form.
-
2Choose the correct sentence.
- They must have finish by now.
- They must be finished have by now.
- They must have finished by now.
- They must finished by now.
Show answer
Answer: C They must have finished by now.
A confident guess about the past takes must + have + participle.
-
3Choose the correct sentence.
- You could warned me.
- You can have warned me.
- You could have warned me.
- You could have warn me.
Show answer
Answer: C You could have warned me.
A missed chance takes could + have + participle.
-
4Choose the correct sentence.
- He must not have known about the meeting.
- He can’t knew about the meeting.
- He can’t have knew about the meeting.
- He can’t have known about the meeting.
Show answer
Answer: D He can’t have known about the meeting.
The confident negative about the past is can’t have.
-
5Fill in the gap.
I _____ have said that — I am sorry.
- must not
- can not
- could not
- should not
Show answer
Answer: D I should not have said that — I am sorry.
Regret about something you did takes should not have.
-
6Fill in the gap.
The window is broken — someone _____ have thrown a stone.
- should
- can’t
- must
- would
Show answer
Answer: C The window is broken — someone must have thrown a stone.
The evidence supports a confident conclusion.
-
7Fill in the gap.
She _____ have missed the bus, but I am not sure.
- might
- must
- can’t
- should
Show answer
Answer: A She might have missed the bus, but I am not sure.
might have leaves it open.
-
8Fill in the gap.
They _____ have arrived yet — the plane landed ten minutes ago.
- must not
- should not
- can’t
- may not
Show answer
Answer: C They can’t have arrived yet — the plane landed ten minutes ago.
You are sure it is impossible, so can’t have.
-
9Put the words in the right order.
I should have asked for a receipt
Show answer
Answer: I should have asked for a receipt.
modal + have + participle, in that order.
-
10Put the words in the right order.
They must have forgotten the appointment
Show answer
Answer: They must have forgotten the appointment.
A confident conclusion about the past.
Practise this lesson in Zorg Space
In the app every rule becomes interactive practice: instant correction, reviews at the moment you are about to forget, and progress you can see from level to level — free.
Start for free