Could have and should have

Could have and should have


The structure could have + past participle is used to guess or speculate about what has happened.

Here are some examples:

She could have gone swimming.

Could have + past participle is also used to say that something was possible but did not happen.

You could have finished it sooner.
That was a bad place to go riding – you could have broken your skull.
You could have done better on your exam.
He could have waited a little longer.
You could have given me another chance.
You could have sent him a letter.

Should have + past participle

The structure should have + past participle is used to talk about
past events which did not happen, or which may or may not have happened.

I should have sent the parcel this morning, but I forgot.
You should have apologized to him.
He should have asked me before borrowing my car.
They should have arrived by now.

Should not have + past participle refers to unwanted things that happened.

You shouldn’t have called him a fool.