The difference among could have, would have and should have

Today we will take a look at the modal verbs “could have”, “would have” and “should have”. These past modal verbs are useful for expressing your present feelings about a past decision (or another action).

1. Could have

“Could have” means that something was possible in the past, but it did not happen.

I could have gone directly to college, but I decided to travel for a year.

You can say “I couldn’t have said it better myself” when you like the way somebody said something. It is a way to show strong agreement.

“Could not have” means that something was impossible in the past.

She could not have been on that flight because I just saw her at work.

2. Would have

We can use the structure “I would have A, but I had to B” to show that you wanted to do something in the past, but you could not.

I would have called, but there was no phone service.

“Would have” also forms the result clause of a past unreal conditional. For example:

If I had known they were vegetarians, I would have made a salad.

3. Should have

“Should have” means that something did not happen, but we wish it had happened.

I’m sorry that I’m late for work. I should have woken up earlier.

You can use “should have + by now” to refer to something that should be happening now, but it has not happened.

The plane should have arrived by now.