Modal verbs provide additional meaning to the main verbs in a sentence, such as certainty, possibility and ability. There are single concept modal verbs that have one meaning and double concept modal verbs that have two meanings depending on context. Modal verbs do not have infinitives, "-ing" forms or all tenses. Their meanings can also change in questions and negatives. Common modal verbs discussed are can, could, may, might, will, would, shall, should, must and have to.

1. MODAL VERBS
Wipawee Khantikittikul no.9
Preechaya Phacharoen no.14

2. Modal Verbs
Modal verbs are auxiliary verbs
that provide additional and
specific meaning to the main
verbs of the sentence
We use modal verbs to show if
we believe something is
certain, probable or possible
and we also use to do things
like talking about ability,making
requests and offers

3. From..
Modal verbs do not have infinitives or -ing forms
Ex. to can/caning or to must/musting
Modal verbs are followed by an infinitive without to
Ex. We should have gone the other way.
Modal verbs do not have all the tenses
Modal verbs use other verbs to complete the tenses
- Can is complete with be able to
- Must is complete with have to
Ex.
They can play the piano They will be able to play the piano
You must com early You have to come early

4. Modal verbs can have more than one
meaning depending on the situations
1.Single Concept Modal : They have one meaning
2.Double Concept Modal : They have two meaning
3.Modals in past : They are used to express a
situation in the past

5. Single Concept Modal
Modal Concept Example
Will Future Joe will travel to NY next
week
Might Small probability I might move to Canada
some day
Should Recommendation You should go to the
doctor
Ought to Formal recommendation We ought to know about
first aids
Had better Warning I had better study or I
will fail the test

6. Double Concept Modal
Modal Concept Example
Shall(1)
Shall(2)
Educated expression offer
Contractual obligation
Excuse me, I shall go now Shall I clean
it?
The company shall pay on January 1st
May(1)
May(2)
Permission
Good probability
May I come in?
We may visit Mexico this summer.
Must(1)
Must(2)
Responsibility
Assumption
Everyone must pay taxes
She didn’t arrive. She must be sick
Would(1)
Would(2)
Past(used to)
Present unreal
When I was young , I would play soccer
I would buy the car but can’t afford it.
Could(1)
Could(2)
Unreal Ability
Past Ability
I could go if I had time
She could play the piano
Can(1)
Can(2)
Present ability
Permission
We can speak English
Can I have a candy?

7. Modals in the past
They are modals referred to actions that
happened in the past
Structure
MODAL + HAVE + verb in the participle
Ex.
It must have been a difficult decision.

8. May , Might
We can use may to ask for permission and we also use
may to suggest something is possible.
Ex.
May I borrow your pen?
It may rain later today.
We use might to suggest a small possibility of
something.In the past we use might have
Ex.
It might rain this afternoon.
I might have dropped it in the street.

9. Form..
Formal Permission / Formal Prohibition
- Structure
may/may not + base form of the verb
Ex. You may start your exam now.
You may not wear sandals to work.
Polite Request
-Structure
May + subject + base form of the verb
Ex. May I help you?
Polite Suggestion
-Structure
might + base form of the verb
Ex. You might like to try the salmon fillet.

10. Possibility / Negative Possibility
- Structure
may/might + base form of the verb
Ex. Our company might get the order if the client
agrees to the price.
may not/might not + base form of the verb
Ex. Adam and Sue may not buy that house.It’s very
expensive.
To make a suggestion (when there is no better
alternative)
-Structure
may as well/might as well + base form the verb
Ex. You may as well come inside.John will be come
soon

11. Shall , Should , Ought to , had
better
Shall use for obligation in very formal situations.
Should is often used to give an opinion , to make
a suggestion , express a preference or an idea.
Ought to is theoretically possible , but is rarely
used with this meaning
Had better is used for more urgent advice with
bad consequences if you don’t follow it.

12. Form..
To Offer of Assistance or polite suggestion(when
you are quite sure of a positive answer)
- Structure
Shall + subject + base form of the verb
Ex. Shall we go for a walk?
Note: Shall is only used with I or we.It is used
instead of will only in formal English.
(When you are not sure of a positive answer)
- Structure
Should + subject + base of form of the verb
Ex. Should I go for a walk?

13. A prediction or Expectation that something will
happen
- Structure
Should/Shouldn’t + base form of the verb
Ex. I shouldn’t be late. The train usually arrives on
time.
To give advice
- Structure
Should/ought to + base form of the verb
Ex. You ought to have your car serviced before the
winter.
- To give advice in somethings that unacceptable
structure is should’t + base form of the verb
Ex. James shouldn’t teach him words like those.

14. Will , Would
 We use will when we talk about the future or to say what we believe will happen.
 Use when we talk about what people want to do or are willing to do.
 To make promises and offers.
Structure: S + will + infinitive +…
Negative form: S + will not + infinitive +…
Example: I will go to Chiang Mai next week.
I will take care of my mom.
It will rain tomorrow.
Negative form Example: He won’t help her. You’ll not be alone.

15. Will , Would
Would is the past tense form of will
Structure: S + would +infinitive +..
Example:
He said he would do his homework.
If I were a president, I would cut the cost of education.
When I was a kid, I would always go to the beach.
I said I wouldn’t help you.

16. Will , Would
Will and Would in question sentence.
Structure: Will, would + S + please + infinitive +
..
** mostly we use would and we put please after
Subject to make it more polite **
Example: Would you please turn off the light?
Will you please sent me the phone?

17. Can , Could
Can is used to express ability or opportunity, to request or offer
permission, and to show possibility or impossibility.
Structure: S + can + infinitive +..
Example: I can speak Chinese.
I have some free time. I can help her now.
Negative sentence: S + cannot + infinitive +..
Example: Frank can’t drive.
I cannot dance.

18. Can , Could
"Could" is used to express possibility or past ability as well as to
make suggestions and requests.
Could is also commonly used in conditional sentences as the
conditional form of "can.”
Structure: S + could + infinitive +..
Example: I could play the piano.
John could go to jail for stealing the money
Conditional sentences:
Ex: If I had more time, I could travel around the world.

19. Can , Could
REMEMBER: “Could not” vs. “Might not”
"Could not" suggests that it is impossible for something to
happen. "Might not" suggests you do not know if something
happens.
Example:
Jack might not have the key.
*Maybe he does not have the key*
• Jack could not have the key.
*It is impossible that he has the key*

20. Can , Could
Question Sentence
Structure: Can, Could + S + infinitive +..?
*could more polite*
Example: Could I say something please?
Can I use your toilet please?

21. Must , Have to
Structure: S + must, have to + infinitive +..
**We can use 'must' to show that we are certain something is true.
Ex. There's no heating on. You must be freezing.
You must be worried that she is so late coming home.
• **We also use 'must' to express a strong obligation. When we use
'must' this usually means that some personal circumstance makes the
obligation necessary. And we can use ‘have to’ too
• Ex. I must go to bed earlier.
• You have to pass your exams or the university will not accept you.

22. Must , Have to
Negative form
**Must not**
Must not means you are not allowed to do it.
Structure: S + must not + infinitive +...
Ex. You must not smoke in the hospital.
You must not break the law.

23. Must , Have to
**don’t/doesn’t have to**
Means it not necessary to do it. You can do or not it’s up to you.
Structure: S + don’t/doesn’t + have to + infinitive
Ex. You don’t have to return the money to me.
He does not have to come to work tomorrow.
**** or you can use need not it’s have the same meaning as don’t have
to ****