English Class Name: / Date: / Monday Tuesday Wednesday Thursday Friday Saturday Sunday Modal Verbs CAN (present) Ability COULD BE ABLE TO (past) (other tenses) Advice SHOULD OUGHT TO (formal) Obligation MUST HAVE TO (present, sense (external authority, of duty) other tenses) Permission / Request CAN COULD WILL/WOULD MAY (informal) (polite) (neutral) (polite) (formal) Possibility / Deduction MAY/MIGHT MUST CAN’T (weaker possibility) (sure) (impossible) Lack of Obligation DON’T HAVE TO NEEDN’T Prohibition MUSTN’T CAN’T (sense of duty) (external authority) photos in this museum.