2. Logical Assumptions/Deductions (+) MUST: sure/certain that sth is true Used in affirmative sentences, it expresses positive logical beliefs or deductions: You have been practising all day, you must be exhausted.
3. Logical Assumptions/Deductions (-) CAN’T/COULDN’T: certain that sth is NOT true/real. Used in negations, express negative logical assumptions: That can’t be my husband, he’s in London.