Modals are a type of verb that express modality such as ability, permission, obligation, or possibility. The modal verbs in English include can, could, may, might, must, will, would, shall, should, ought to, had better, and have to. Modals give additional meaning to the main verb and have grammatical properties that distinguish them, such as not having different tenses. They express different types of modality including epistemic (likelihood), deontic (permission/duty), and dynamic (ability/willingness). Each modal has specific meanings and uses depending on whether it expresses possibility, necessity, permission, advice, or other functions.

1. Modals

2. Modals
A Modal verb is a type of verb that is used to indicate modality –
that is: likelihood, ability, permission, request, capacity,
suggestions, order, obligation, or advice. Modal verbs always
accompany the base (infinitive) form of another verb having
semantic content.
In English, the modal verbs commonly used are can, could, may,
might, must, will, would, shall, should, ought to, had better, have to
and sometimes need or dare. In English and other Germanic
languages, modal verbs are often distinguished as a class based
on certain grammatical properties.

3. Modals
A modal auxiliary verb gives information about the function of the
main verb that it governs. Modals have a wide variety of
communicative functions, but these functions can generally be
related to a scale ranging from possibility ("may") to necessity
("must"), in terms of one of the following types of modality:
epistemic modality, concerned with the theoretical possibility of
propositions being true or not true (including likelihood and
certainty)
deontic modality, concerned with possibility and necessity in
terms of freedom to act (including permission and duty)
dynamic modality, which may be distinguished from deontic
modality in that, with dynamic modality, the conditioning factors
are internal – the subject's own ability or willingness to act.

4. Modals
The following sentences illustrate epistemic and deontic uses of
the English modal verb must:
epistemic: You must be starving. ("It is necessarily the case that
you are starving.")
deontic: You must leave now. ("You are required to leave now.")
An ambiguous case is You must speak Spanish. The primary
meaning would be the deontic meaning ("You are required to
speak Spanish.") but this may be intended epistemically ("It is
surely the case that you speak Spanish.")

5. Modals
Modal auxiliary Epistemic sense Deontic sense Dynamic sense
can That can indeed hinder.
You can sing
underwater.
She can really sing.
could That could happen soon. -
He could swim when
he was young.
may That may be a problem. May I stay? -
might The weather might improve. - -
must It must be hot outside.
Sam must go to
school.
-
shall - You shall not pass. -
should That should be surprising. You should stop that. -
will She will try to lie. I will meet you later. -
would
Nothing would accomplish
that.
-
We would eat out on
Sundays.

6. LIST OF MODAL VERBS
• Can
• Could
• May
• Might
• Must
• Have to
• Shall
• Should
• Will
• Would
• Ought to
Modal verbs are sometimes referred to as
Modal Auxiliary verbs because they help
other verbs
They are Auxiliary verbs that provide
additional and specific meaning to the
main verb of the sentence

7. How do we use modals?
Example: Milo can play the piano
S
Subject
V
Verb
M
-they are not conjugated
- they don’t need other auxiliary verbs

8. Form
He can ski not He cans ski or He can skis.
Would you like to come with me?
Do you would like to come with me?
They can’t be serious.
They don’t can be serious.
There is no “s” in singular
There is no “do / does” in the question
There is no “don’t / doesn’t” in the negative

9. Form
to can / caning to must /musting
She must study.
He could play football in his youth. (general ability)
We should have gone the other way.
Modal verbs do not have infinitives or –ing forms
Modal verbs are followed by an infinitive without to

10. Form
Modal verbs do not have all the tenses
Many modals cannot be used with the past or the future tenses
Can - be able to
Must - have to
I can solve the problem. – I was able to solve the problem.
You must come early. – You had to come early yesterday.

11. Modals
Modal Verb Expressing Example
must
Strong obligation You must stop when the traffic
lights turn red.
logical conclusion / Certainty He must be very tired. He's
been working all day long.
must not
prohibition You must not smoke in the
hospital.
can
ability I can swim.
permission Can I use your phone please?
possibility Smoking can cause cancer.
could
ability in the past When I was younger I could run
fast.
polite permission Excuse me, could I just say
something?
possibility It could rain tomorrow!
may
permission May I use your phone please?
possibility, probability It may rain tomorrow!

12. Modals
Modal Verb Expressing Example
might
polite permission Might I suggest an idea?
possibility, probability I might go on holiday to
Australia next year.
need not
lack of necessity/absence of
obligation
I need not buy tomatoes. There
are plenty of tomatoes in the
fridge.
should/ought to
50 % obligation I should / ought to see a doctor.
I have a terrible headache.
advice You should / ought to revise
your lessons
logical conclusion He should / ought to be very
tired. He's been working all day
long.
had better
advice You 'd better revise your
lessons

13. CAN
1) to express ability:
Ryan can speak French but he cannot speak German.
I can write a poem.
2) to express request:
Can you help Sue?
3) to express permission:
Can I use your cell phone?
Can I say something?
4) to express possibility:
If the weather is perfect tomorrow, we can go on a picnic.
I can be late.

14. COULD
1) to express abilities in the past:
Jason could talk when he was four.
2) to express permission:
Could I leave the classroom?
3) to express future possibility:
I could get a bad final mark. It depends on the next exam.
4) could with present perfect tense is used to express something
in the past may be real.
You could have been killed in that accident.
I could have won that game.

15. SHALL
1) to express the simple future for the first person.
• Shall we meet at the bus stop?
• I shall never forget your help.

16. WILL
1) present to future tense:
Sean will leave tomorrow. She will be
back in a few days.
If it rains, the soccer game will be put off.
2) express willing,
If you won’t go and help him, I will.
I will wash the dishes if you cook.

17. WOULD
1) as the past tense of will:
She said she would buy dinner on her way home.
I believed it would rain so I brought my raincoat.
2) to express polite request:
Would you please take off your coat?
Would you mind turning the radio off?

18. SHOULD
1) to give advice and opinions
You are driving too fast; you should slow down a little bit.
You have gained a lot of weight. You should go on a diet.
2) to express expectations:
Are you ready? The taxi should be here soon.
Twenty dollars is enough. It shouldn’t cost more than that.
3) to suggest a less strong possibility
If you should pass the bakery, can you buy some bread?
Should with present perfect tense means something in the
past should not be done.
The baby is crying. You shouldn’t have talked so loudly.
She is angry. You shouldn’t have come back so late.

19. MUST and HAVE TO
1) express something is necessary and essential
You must pay by cash.
You have to drive on the right in France.
2) Students have to wear uniform.
must not is used to express something is not permitted or
allowed.
You mustn’t smoke, eat and drink in the museum.
You must not drink and drive.
3) not have to is used to express something that is not to be done
necessarily.
We don’t have to get up early on Saturday.
She doesn’t have to live in the hotel. She can live with us.

20. MAY
1) express possibility in the present or in the future.
It may rain.
Elizabeth may know his telephone number.
2) for permission:
May I come in?
You may come if you want.
3) to express wish or hope.
May you live a long life!

21. MIGHT
1) to express possibility in the present or in the future.
Ashley might be in the library. I am not sure.
George might come as well.
He may come.
He might come. (the chance that he comes is less likely than
may)
2) might with present perfect tense means speculation about the
past.
Edward is late. He might have missed his bus or he might
have overslept.

22. Past Modals
These past modal verbs are all used hypothetically, to talk about
things that didn't really happen in the past.

23. Past Modals
1: Could have + past participle means that something was
possible in the past, or you had the ability to do something in the
past, but that you didn't do it. I could have stayed up late, but I
decided to go to bed early.
They could have won the race, but they didn't try hard enough.
Julie could have bought the book, but she borrowed it from the
library instead.
He could have studied harder, but he was too lazy and that's why he
failed the exam.
Study smart, not hard.
Do not study hard, study smart.

24. Past Modals
Couldn't have + past participle means that something wasn't
possible in the past, even if you had wanted to do it.
I couldn't have arrived any earlier. There was a terrible traffic jam (=
it was impossible for me to have arrived any earlier).
He couldn't have passed the exam, even if he had studied harder. It's
a really, really difficult exam.

25. Past Modals
2: We use could have + past participle when we want to make a guess
about something that happened in the past. In this case, we don't know if
what we're saying is true or not true. We're just talking about our opinion of
what maybe happened.
Why is John late?
He could have got stuck in traffic.
He could have forgotten that we were meeting today.
He could have overslept.
We can also choose to use might have + past participle to mean the same
thing:
He might have got stuck in traffic.
He might have forgotten that we were meeting today.
He might have overslept.

26. Past Modals
1: Should have + past participle can mean something that would have
been a good idea, but that you didn't do it. It's like giving advice about the
past when you say it to someone else, or regretting what you did or didn't do
when you're talking about yourself.

27. Past Modals
Shouldn't have + past participle means that something wasn't a good
idea, but you did it anyway.
I should have studied harder! (= I didn't study very hard and so I failed the
exam. I'm sorry about this now.)
I should have gone to bed early (= I didn't go to bed early and now I'm tired).
I shouldn't have eaten so much cake! (= I did eat a lot of cake and now I
don't feel good.)
You should have called me when you arrived (= you didn't call me and I was
worried. I wish that you had called me).
John should have left early, then he wouldn't have missed the plane (= but
he didn't leave early and so he did miss the plane).
Easy come, easy go.

28. Past Modals
2: We can also use should have + past participle to talk about something
that, if everything is normal and okay, we think has already happened. But
we're not certain that everything is fine, so we use 'should have' and not the
present perfect or past simple. It's often used with 'by now'.
His plane should have arrived by now (= if everything is fine, the plane has
arrived).
John should have finished work by now (= if everything is normal, John has
finished work).
We can also use this to talk about something that would have happened if
everything was fine, but hasn't happened.
Lucy should have arrived by now, but she hasn't.

29. Past Modals
Would have + past participle
1: Part of the third conditional.
If I had had enough money, I would have bought a car (but I didn't have
enough money, so I didn't buy a car).

30. Past Modals
2: Because 'would' (and will) can also be used to show if you want to do
something or not (volition), we can also use would have + past participle
to talk about something you wanted to do but didn't. This is very similar to
the third conditional, but we don't need an 'if clause'.
I would have gone to the party, but I was really busy.
(= I wanted to go to the party, but I didn't because I was busy. If I hadn't
been so busy, I would have gone to the party.)
I would have called you, but I didn't know your number.
(= I wanted to call you but I didn't know your number, so I didn't call you.)

31. Must vs. have to
Both must and have to express obligation or necessity, but there are some
small differences:
• Must expresses the speaker's feelings, whereas have to expresses, above
all, an impersonal idea:
You must come. You are obliged to come (I require that you come)
You have to come. You are obliged to come. (There's a rule requiring you to
come)
Must I wear this tie? Am I obliged to wear this tie? (What do you think?)
Do I have to wear this tie? Am I obliged to wear this tie? (Is there a rule
about ties?)
• Have to mainly expresses general obligations, while must is used for
specific obligations:
I have to brush my teeth twice a day.
I must tell you something.

32. Must vs. have to
Important: To express obligation, duty or necessity in the future or the past,
must and need are not used. They are replaced by have to:
We must (need to) buy another ticket.
We had to buy another ticket yesterday.
We'll have to buy another ticket later.
However, in their negative forms, mustn't and don't have to have completely
different meanings:
• Mustn't expresses prohibition
You mustn't drive. You are prohibited to drive. You are not allowed to drive.
• Don't have to expresses the absence of obligation or necessity:
You don't have to drive. You are not obliged to drive (but you can if you want
to).

33. Resources
https://www.gymglish.com/en/gymglish/english-grammar/must-vs-have-
to
https://www.perfect-english-grammar.com/modal-verbs.html
https://www.perfect-english-grammar.com/could-have-should-have-would-
have.html