1. 8. Modal Verbs

2. Introduction
Modals are special words in English and are used for specific purposes. They are NOT verbs.
The modals are: can, could, had better, may, might, must, ought to, shall, should, will, would.
Phrasal modals: be able to, be going to, be supposed to, have to, have got to.
The form is: Subject + Modal + Verb
She can sing very well.

3. Expressing Ability: can, can’t, could, couldn’t
In the present: A cat can climb trees but it can’t swim.
In the past: Our son could walk when he was one year old but he couldn’t talk.
Expressing Possibility: may, might, could
It may rain tomorrow.
Where is Dave? I don’t know. He might be stuck in traffic.
Where are the pens? They could be in the drawer.

4. Expressing Permission: may, can
John was sick so he may submit his essay late.
You can park your car on this street but not on the next one.
Giving Advice: should, ought to, had better
You should be on time for class or your teacher will be angry.
You ought to have your passport when you cross the boarder.
You had better clean the house before your guests arrive.

5. Expressing Necessity or Lack of Necessity: must, have/had to, have got to, don’t/didn’t have to
You must have a visa to enter Cambodia.
Matt has to meet with the director on Friday.
They had to take the bus because their car broke down. (past tense)
I have got to go or I will be late for my meeting.
“have got to” is informal and used in spoken English only. The usual pronunciation of “got to” is “gotta” and sometimes “have” is omitted... “I gotta go.”
She doesn’t have to work on Monday so we can stay in New York for an extra day.
We didn’t have to bring lunch. It was provided. (past tense)

6. Expressing Prohibition: must not, can’t, had better not
You can’t swim in the Rideau Canal.
When my mother is here you had better not talk about politics.
You must not open your gift until your birthday.
Expressing logical conclusions: must, must not
Nancy is coughing a lot. She must be sick.
Rick took the olives off of his pizza. He must not like olives.

7. Requests: may, could, can, would, will
May I borrow your pen?
Could you pass me that book?
Can I use your computer tonight?
Would you please open the window?
Will you please lend me $10?
Expressing Obligation: be supposed to
I am supposed to take care of my sister’s children tomorrow.
She was supposed to call me yesterday but she didn’t. (when used in the past, “was supposed to” indicates that an action that was expected, did NOT happen)

8. Making Suggestions: could, should, could have, should have
What should we do tomorrow? We could go fishing or we could go on a picnic. (“could” expresses choices)
If you are having trouble with your English class, you should talk to your teacher. (“should” offers a stronger suggestion; advice)
Jerry could have gone to a movie or gone shopping. Instead he stayed home. (“could have” expresses choices in the past.)
I failed my Math test! I should have studied more! (“should have” gives advice that applies to a past situation.)

9. Degrees of Certainty
Modals can be used to express how sure you are that something is true.
In the present we use: must be, may be, might be and could be
100% certain:
Carbon dioxide is contributing to global warming. (no modal)
95% certain:
Carbon dioxide must be contributing to global warming.
50% certain or less:
Carbon dioxide may be / might be / could be contributing to global warming.

10. In the present negative we use: couldn’t be, can’t be, must not be, may not be, might not be.
100% certain:
She is not hungry. (no modal)
99% certain:
She couldn’t be hungry.
She can’t be hungry.
95% certain:
She must not be hungry.
50% certain or less:
She may not be hungry.
might not be hungry.

11. In the past we use: must have been, may have been, could have been.
Affirmative
Negative
100% certain:
He was sick. (no modal)
95% certain:
He must have been sick.
50% certain or less:
He may have been sick.
He might have been sick.
He could have been sick.
100% certain:
He was not sick. (no modal)
99% certain:
He can’t have been sick.
He couldn’t have been sick.
95% certain:
He must not have been sick.
50% certain or less:
He may not have been sick.
He might not have been sick.

12. In the future we use: should, ought to, may, might, could
100% sure:
Ben will do well on the test. (no modal)
90% certain:
Ben should do well on the test.
Ben ought to do well on the test.
50% certain and less:
Ben may do well on the test.
Ben might do well on the test.
Ben could do well on the test.