modal auxiliary verbs of probability in the past

MODAL AUXILIARY VERBS OF PROBABILITYModals of Probability and Certainty: WILL, MUST, SHOULD, MIGHT,COULD, MAY, CAN’T.These are used to make guesses or logical deductions about people orthings. These deductions can be made according to the present, future orpast.A) WILL and WON’T are used to express what we believe or guess to betrue about the present. They indicate an assumption based on ourknowledge of people and things, their routines, character, and qualities.Example: “I wonder what my husband is doing”. “Well, it’s Saturday night, soI guess that right now he’ll be dancing with a blonde woman at the disco.”Example: “Someone’s knocking at the door, but it’s so late!”“That won’t be the postman.B) MUST is used to express the most logical or rational interpretations of asituation. We do not have all the facts, so it is less certain than WILL.Example: Alf is a very good tennis player and not many players beat him.But yesterday he played against Bill and Bill won. So:“Bill must be a very good player “(otherwise he wouldn’t have won).The negative of this use is CAN’T. We use can’t to say that we thinksomething is impossible.Example: “You’ve only just had dinner. You can’t be hungry already. “(It isimpossible that you are hungry).C) SHOULD is used to express what may reasonably be expected tohappen. This use of SHOULD has the idea of if everything has goneaccording to the plan.Example: “This homework shouldn’t take you too long. “(if you ´veunderstood what you have to do.)“Our guests should be here soon. “ (If they haven’t got lost)D) MAY is used to express the possibility that an event will happen or ishappening.

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!”