4.143 uncertainty: 'could have', 'might have', 'may have'

You also use 'could', 'might', or 'may' with 'have' to say that it is possible that something was the case, but you do not know whether it was the case or not.

• It is just possible that such a small creature could have preyed on dinosaur eggs.
• Grandpapa might have secretly married Pepita.
• I may have seemed to be overreacting.