MODAL VERBS - OBLIGATIONS
AND PROHIBITIONS
When we want o express
permission, responsibilities, obligation or prohibition we use modal verbs .
HAVE TO AND MUST are used to express obligation.
DON’T HAVE TO is used to
express that something is not required / external obligation
MUSTN’T is used to express
prohibition
MUST
MUST and MUSTN’T are the same
for all persons¢
We use MUST when we think it is important to do an action
or we give people¢ orders.
You MUST be home by eleven
She MUST tidy up her room
every day
We use MUST when the
obligation comes from¢ the speaker.
I must go to the doctor, I
don’t feel well.
I must have my homework ready
tonight
I
must stop smoking.
HAVE TO
We use HAVE TO when the
obligation comes¢ from someone else, not the speaker; for an action that is necessary
because of rules.
We HAVE TO be at the airport
three hours before the flight leaves.
At work I HAVE TO wear a
uniform
My father HAS TO pay the rent
every month.
MUSTN`T
MUSTN’T is used to say that
something is against the rules or against the law.
You MUSTN’T smoke at school.
You MUSTN’T
use your telephone on a plane.
EXERCISES
Choose the correct modal verb
to fill in the spaces in blank.
1. You _____ come to the
meeting, but it will be nice if you are there. (mustn’t- don’t have to)
2. You ______ start saving
money if you want to retire in a few years. (must- have to)
3. We _________ to visit the
doctor every year because the Social Security requires it. (must- have to)
4. I ______ call my dad every
day. (must- have to)
5. My brother _______ wear a
tie at work, I do. (mustn’t – doesn’t have to)
6. You _____ eat healthier
and stop smoking, you will feel better. (must have to)
7. I _____ study tonight, my
exam is tomorrow. (must- have to)
8. People ______ drink and
drive cars. It is prohibited (mustn’t - don’t have to)
9.
John can’t come because he ____ work tomorrow. (must- has to)
10.We _______ speak when the
teacher is speaking. (mustn’t- don’t have to)
11.
I can hear you. You _______ shout. (mustn’t - don’t have to)
12. She has a big problem. We
______ help her. (must- have to)
13. You ______ send a
document without reading it first. (mustn’t – don’t have to)
Choose have to / has to or
don't have to / doesn't have to.
1. Every man ………… do military
service in my country. It's obligatory.
2. When do we ………… pay for
the next term?
3. Policemen ………… wear a
uniform.
5. Does Susan ………… work long
hours?
6. I …………. get up early on Sundays.
I can stay in bed.
7. You have ………….. a visa to
come to Ukraine
8. You …. to do it if you
don't want to.
9. My daughter ….. to cook, because I cook for the whole family.
10. We ….pay. It's free.
