PAST MODALS - SHOULD/COULD/WOULD HAVE (B1 Grammar)
Use past modals (should have, could have, would have + past participle) to talk about the PAST: regrets, criticism, missed opportunities, or past possibilities that didn't happen.
Quick tip: SHOULD HAVE = regret/criticism (right thing not done). COULD HAVE = past possibility (ability not used). WOULD HAVE = past conditional/intention.
SHOULD HAVE = Regret or criticism
Use SHOULD HAVE when you regret something you DIDN'T do, or to criticize past actions. It was the right thing to do, but you didn't do it.
I should have studied more. (regret - I didn't study enough)
You should have called me. (criticism - you didn't call)
She should have left earlier. (regret - she didn't leave early)
They should have been more careful. (criticism - they weren't careful)
COULDHAVE = Past possibility that didn't happen
Use COULD HAVE for past possibilities or abilities that weren't used. You had the ability/opportunity, but didn't use it.
I could have helped you. (I had the ability, but didn't)
She could have gone to university. (she had the opportunity, but didn't)
We could have won. (it was possible, but we didn't)
He could have been a doctor. (he had the ability, but didn't become one)
WOULD HAVE = Past conditional result
Use WOULD HAVE in Third Conditional (if I had..., I would have...). Also for past intentions that didn't happen.
If I had known, I would have come. (Third Conditional)
I would have called, but I forgot. (past intention that didn't happen)
She would have helped, but she was busy. (past intention)
Common mistakes
Not "I should studied more." — say "I should have studied more.". Past modals need HAVE + past participle. Should have (not should) + past participle..
Not "I could of helped." — say "I could have helped.". Always use HAVE (not 'of'). Could have sounds like 'could of' but is always written 'could have'..
Practise it
Regret/criticism? SHOULD HAVE. Past possibility? COULD HAVE. Past conditional? WOULD HAVE. Always use HAVE + past participle!