Grade 9 · English · Grammar in Use (Modal Auxiliaries)
Modals: can, could, may, might, must, should, would, ought to. Uses: ability (can), permission (may), possibility (might), obligation (must), advice (should), prohibition (must not). Perfect modals refer to the past: should have (a missed duty), could have (a missed chance), might have (past possibility), must have (past certainty).