1. Modal verbs
• Modals verbs are auxiliary verbs, which means that they
accompany the main verb in a sentence.
• They can be used to express ability, permission, obligation,
possibility and suggestion, among other ideas.
• You don´t conjugate a modal verb.

2. Advice
Should
Deber (consejo)
CAN
Poder (habilidad)
Must
deber
(obligaciones)
Jack should go
to the doctor.
Have to
Tener que
(Obligación)
I have to study
for the quiz.
Obligation

3. Can
(ability and permission)
• We use can to talk about ability and permission
• I can speak English.
• Can I go to the bathroom?
Can´t
(prohibition)
• You use can to talk about prohibition
• You can´t wear shoes in the temples.

4. Have to (necessity)
Use have to to explain than something is necessary.
Example :I have to do my homework.
To express obligation from an external authority.
Mother: You have to clean your room.
Do you have to be at school at 6:30?
Don´t/ doesn´t have to
(lack of necessity )
You use don´t have to/ doesn´t have to: to talk about something that is not
necessary.
• You don´t have to bring any gift when you visit someone.
• She doesn´t have to wear a uniform.

5. Should
(suggestion)
• People should sleep 8 hours at
night.
• People shouldn´t /should not
sleep less that 8 hours at night.
• Should we invite Karol to the
party?

6. Must
(obligation)
• I must pay the rent today.
• Must we stand up when the teacher arrive?
mustn´t
(prohibition)
• You musn´t / must not bring phones to the school.

7. Difference between must and have to
• Must is used to refer to an
action that we impose on
ourselves or on others. (se
refiere a una obligación entre
dos personas, o una obligación
con uno mismo.)
• EX: I must go to bed. I’m
exhausted. ( Debo ir a la cama.
Estoy exausto)
• Have to is used to refer to
an external obligation. (se
refiere a una obligación externa, es
algo que si no lo haces, hay
consecuencias)
• Ex: We have to leave now or
we’ll miss our flight(Debemos
irnos ahora o perderemos
nuestro vuelo)