MODAL VERBS

General rulesThey 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)

MOST COMMON MODAL VERBS

CAN

COULD

HAVE TO

MUSTMIGHT/

MAY

SHOULD

ABILITY

It is expressed with CAN (present) and COULD (past)

- I can speak English since I was 15.

- When my father was young he could run 10 km in 15 minutes.

The negative is formed by adding NOT to the modal verb

- He can’t run for long because he suffers from asthma.

- There were lots of people at the concert, so we couldn’t move.

Questions are made by inverting the SUBJECT and VERB

- How long can you resist under the water without breathing?

- Could you read properly when you were five years old?

OBLIGATION

IN AFFIRMATIVE it is expressed with MUST and HAVE TO

- Students must be in the classroom before the teacher arrives

- My friend has to wear uniform at her school.

IN NEGATIVE they have different meanings

MUST expresses OBLIGATION/ PROHIBITION

- We mustn’t enter while they are playing.

HAVE TO expresses NO OBLIGATION (absence of obligation)

- You don’t have to do exercise 3 if you don’t want to.

(Difference)

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)

POSSIBILITY and CERTAINTYMUST

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

Some practice:CAN’T and MUST

COULD, MAY, MIGHT