This document introduces modal verbs and their uses to express ability, obligation, and possibility in English. It provides examples of common modal verbs like can, could, have to, must, might, and may and how they are used in the affirmative, negative, and questions. It also distinguishes how must and have to are used to express obligation and prohibition versus absence of obligation. Finally, it gives examples of modal verbs that express certainty versus possibility.

1. MODAL VERBS INTRODUCTION TO © 2011- 4º E.S.O by Beni Suárez Prado

2. General rules They help to express different meanings: ABILITY, OBLIGATION, OR POSSIBILITY They do not take -S for 3rd person ( except HAVE TO) They lack most tenses and forms They are followed by infinitive without TO (except HAVE TO)

3. MOST COMMON MODAL VERBS CAN COULD HAVE TO MUST MIGHT/MAY SHOULD

6. Some practice: CAN, COULD, CAN’T, COULDN’T Exercise 1 Exercise 2 MUST, HAVE TO, MUSTN’T, DON’T HAVE TO Exercise 3 ( must , have to ) Exercise 1 ( must ) Exercise 2 ( have to ) Exercise 4 ( mustn’t ) Exercise 5 ( mustn’t , don’t have to ) Exercise 6 ( must , have to , mustn’t , don’t have to )

7. POSSIBILITY and CERTAINTY MUST CAN’T COULD MAY MIGHT We are CERTAIN that something it’s true DOUBT Sophie must be at work, it’s ten o’clock and she works from 8 to 2 pm I haven’t got any homework, I could go to the beach this afternoon I must help my mum, afterwards, I may go to the beach I might go to the beach, but I’m not sure because I’m really busy today. Sophie can’t be at work, it’s half past three. We are CERTAIN that something it’s NOT true

8. Some practice: CAN’T and MUST COULD, MAY, MIGHT