Use may, might, could, must, and can't to express different degrees of certainty about something.
I'm sure it's true. Example: She must be tired (I can see it).
Maybe true. Example: It may rain later.
I'm sure it's not true. Example: That can't be Tom — he's in Paris!
must (100% sure positive) > may/might/could (maybe) > can't (100% sure negative).
must (100% sure positive) > may/might/could (maybe) > can't (100% sure negative).I'm sure it's true. Example: She must be tired (I can see it).Maybe true. Example: It may rain later.I'm sure it's not true. Example: That can't be Tom — he's in Paris!