modal auxiliary verbs of probability in the past

Example: “You are looking for Jack. Nobody knows for sure where he is butyou get some suggestions. He may be in his office.”“Where’s Ann?” “She may be having a bath, I don’t know.”E) MIGHT is more tentative and slightly less certain than MAY.Example: “It might rain. Take your umbrella.”F) COULD has a similar meaning to MIGHT.Example: “You could be right. I’m not sure”G) COULDN’T has a similar meaning to CAN’T but is slightly weaker.Example: She couldn’t have a ten-year-old daughter! She’s only 21 herself!MODAL AUXILIARY VERBS OF PROBABILITY IN THE PASTThey express the same degrees of certainty. (WILL HAVE DONE is themost certain, and MIGHT/COULD HAVE DONE is the least certain.Example: “I met a tall girl at your party. Very attractive”.“That’ll have been my sister, Patsy”.“Although they had selected the best hits, nobody danced.”“The music can’t have been any good!”“Bob is never late. I don’t know what could have happened to him”“He might have forgotten his wedding!”