When we look at a situation and must make a conclusion about
what happened, we can use could have/may have and might have + past participle for
possibilities. On the other hand, when we use
couldn't have + past participle , we are saying that it is impossible.
examples
Julia is not here.
She might have gone home.
There are only two stores open, so she may have gone to the
closest one.
Paul has a car, so he could have gone anywhere.
Check you phone because she might have tried to call you.
Gwen doesn't have keys, so she couldn't have taken the car.
Victor forgot his phone, so he couldn't have called you.
You couldn't have seen Pablo at the mall because he is on
vacation in Miami
