90-100% sure it is true
What do we use when we are 90% certain that something was true?
Must have + past participle
What can we use to say that something was possible in the past or someone had the possibility to do something but didn’t do it?
could have + past participle
What do we use to talk about a situation expected to happen in the past? This form is normally used for criticism.
should have/ought to have + past participle
What do we use when we are quite sure that something did NOT happen or was NOT true in the past?
Can’t/couldn’t have + past participle
What can we use to say that it’s possible that something was true or happened in the past?
could/might/may have + past participle
I _______ (revise) more for the exam. I was lazy, and now I'll fail!
should have revised
Sarah looked very happy. She ______ (pass) her driving test.
must have passed
Nobody knows exactly why he died. But we think it _______ (be) an accident.
might have been
You _____ (pay) more attention. Now we are lost!
ought have paid
I can't believe Jim hasn't arrived yet. He _____ (take) the right train.
can't have taken
We _______ (buy) enough beer for the party.
may not have bought
We really enjoyed the movie. You ______ (come) with us.
should have come
You ________ (be) ill yesterday. Jessie saw you at the bowling alley.
couldn't have been
I don't know where they went but they ______ (go) to Paris or Marseille.
could have gone
I didn't know you were going to Phil's party yesterday. You ______ (tell) me!
should have told