This document provides information on using have to/don't have to, can/can't, and must/mustn't to express obligations, permissions, abilities, and prohibitions in English. It gives examples of affirmative and negative constructions for each modal verb as well as questions. Key points covered include using have to to express necessity or obligation, don't have to to express lack of necessity or obligation. Can is used to express ability or permission while can't expresses lack of ability or permission. Must conveys strong obligation while mustn't expresses what is not permitted.

1. NAF LEVEL 2 – UNIT 4 GRAMMAR

2. Have to / Don’t have to
• We use have to when we mean «this is
necessary» or you are «obliged to».
Example:
All children have to go to school in this country.
• We use don’t have to when we mean «this is not
necessary» or «you are not obliged».
Example:
Three-year-old don’t have to go to school.

3. Have to / don’t have to
SUBJECT EXPRESSION VERB IN BASE FORM COMPLETMENT
I
have to
don’t have to
study for the test.
You pay attention in class.
We practice our English.
They work every day.
He
has to
doesn’t have to
finish the project today.
She take care of the children.
It be good.
 had to go to school

4. Questions with have to
DO / DOES SUBJECT EXPRESSION VERB BASE FORM COMPLEMENT
Do I
you
we
they
have
to
do the
homework?
Does he
she
it
clean the class?
Did I
you
we
they
he
she
it
read the book?

5. Can / Can’t
• We use can when we mean you «are
able to» or «permitted»
• We use it for «permission»
• We use it to express capacity to do
something.
• We use can’t means «you are not
permitted» or that «you don’t have
capacity to do»

6. Can / can’t
AFFIRMATIVE NEGATIVE QUESTION
I can swim. I can’t swim. Can you swim?
You can stay at
home.
You can’t stay at
home.
Can I stay at
home?
SHORT ANSWERS
Yes, I can. No, I can’t

7. Must / mustn’t
• We use must when we mean that
something is very important and
you are obliged to do it.
• We use mustn’t when we mean
that something is «not
permitted»

8. Must / mustn’t
AFFIRMATIVE NEGATIVE SHORT
ANSWERS
You must clean
your room.
You mustn’t
swim without
warming up. Yes, I must.
No, I mustn’t.
He must respect
his friends.
She mustn’t go
out late.