INTRODUCTION TO
MODAL
VERBS
© 2011- 4º E.S.O by Beni Suárez Prado
General rules
They help to
express different
meanings:
ABILITY,
OBLIGATION, OR
POSSIBILITY
They lack most
tenses and forms
They do not take -S
for 3rd person
( except HAVE TO)
They are followed
by infinitive
without TO
(except HAVE TO)
COULD
CAN
MOST COMMON
MODAL VERBS
HAVE
TO
SHOULD
MIGHT/
MAY
MUST
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
(Difference)
- 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.
Some practice:
CAN, COULD, CAN’T, COULDN’T
Exercise 1
Exercise 2
MUST, HAVE TO, MUSTN’T, DON’T HAVE TO
Exercise 1 (must)
Exercise 2 (have to)
Exercise 3 ( must, 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 CERTAINTY
We are CERTAIN that something it’s true
MUST
Sophie must be at work, it’s ten o’clock and
she works from 8 to 2 pm
COULD
I haven’t got any homework, I could go to
the beach this afternoon
DOUBT
MAY
I must help my mum, afterwards, I may go to
the beach
MIGHT
I might go to the beach, but I’m not sure
because I’m really busy today.
CAN’T
We are CERTAIN that something it’s NOT true
Sophie can’t be at work, it’s half past three.
Some practice:
CAN’T and MUST
COULD, MAY, MIGHT