This document discusses modals of ability and possibility in English. It explains the uses of can, could, be able to for present, past and future ability. Can is used for present ability, could for past ability, and be able to for past, present and future ability. It also discusses modals of future possibility like might, may, could and will. Modals like might, may and could express uncertainty about the future while will is used in yes/no questions about future possibility.

1. Modals of Ability and Possibility
Modals of Ability: Can and Could; Be Able To
Past, Present, and Future Ability
Modals of Future Ability
Grammar Sense 2, Chapter 9

2. Modals of Ability: Can and Could;
Be Able To
 Can for Present and Future Ability
Affirmative Statements Negative Statements
I can play the piano. I cannot (can’t) play the flute.
He can speak Spanish. He can’t speak Arabic.
They can work on their essay tomorrow. They can’t work on their
vocabulary tomorrow.
Yes/No Questions Short Answers
Can you play the piano? Yes, I can./No, I can’t.
Can he speak Spanish? Yes, he can./No, he can’t.
Can they work on their essay tomorrow? Yes, they can./No, they can’t.

3. Modals of Ability: Can and Could;
Be Able To (cont’d)
Information Question
What can you play?
Who can speak Spanish?
How long can they work on their essay tomorrow?
 Could for Past Ability
Affirmative/Negative Statements
I could read in kindergarten./I could not (couldn’t) read in kindergarten.
He could drive at 14./He couldn’t drive at 14.
They could draw beautifully./They couldn’t draw beautifully.
Yes/No and Information Questions
Could you read in kindergarten? Yes, I could./No, I couldn’t.
What could she read in kindergarten?
Who could read in kindergarten?

4. Modals of Ability: Can and Could;
Be Able To (cont’d)
 Be Able To for Past, Present, and Future Ability
(Be able to is not a modal, but it has the meaning as can and could. The verb be in be able to
chances from and agrees with the subject.)
Affirmative Statements
He was able to work yesterday.
He is able to work today.
He will be able to work tomorrow.
Negative Statements
He was not able to work yesterday.
He is not able to work today.
He will not be able to work tomorrow.

5. Past, Present, and Future Ability:
Meaning and Use
 Present Ability with Can
Can is used to talk about an ability in the present.
Examples:The baby can walk, but she can’t talk yet.
Strong winds can cause a lot of damage.
 Future Ability with Be Able To and Can
Use will be able to to talk about a skill or other ability that you don’t have yet,
but will have in the future. Do not use can to describe an ability that you will
have only in the future.
Right: After I complete this class, I’ll be able to speak English well.
Wrong: After I complete this class, I can speak English well.
Use will be able to or can to express ability that relates to decisions and
arrangements for the future.
Example: I’m busy now, but I’ll be able to help you in 10 minutes.
I’m busy now, but I can help you in 10 minutes.

6. Past, Present, and Future Ability:
Meaning and Use (cont’d)
 Past Ability with Could and Be Able To
Use could or was/were able to to talk about an ability that existed for
a long period of time in the past.
Example: When I was young, I was able to/could eat dessert every
night, and I didn’t gain weight.
In affirmative statements with action verbs, do not use could to talk
about an ability related to a single event. Use only was/were able
to.
Example: Yesterday I was able to finish my homework quickly.
Wrong: Yesterday I could finish my homework quickly.

7. Past, Present, and Future Ability:
Meaning and Use (cont’d)
In affirmative statements with certain stative verbs such as see, hear,
feel, taste, understand, and remember, use could or was/were
able to to talk about ability related to a single event in the past.
Example: Last night the sky was clear, and we were able to/could
see for miles.
In negative statements, use couldn’t or wasn’t/weren’t able to for
both ability during single events and ability over a long period of
time.
Examples:
Yesterday I wasn’t able to/couldn’t finish my homework quickly.
When I was younger, I wasn’t able to/couldn’t finish my homework
quickly.

8. Modals of Future Possibility
Affirmative Statements Negative Statements
I might leave tomorrow. I might not leave tomorrow.
You may leave tomorrow. You may not leave tomorrow.
He could leave tomorrow.
They will leave tomorrow. He won’t leave tomorrow.
(Couldn’t is not usually used to express future possibility.)
Yes/No Questions in the Future Form
Are you going to leave next weekend? I may./I may not.
Will you leave next weekend? I might./I might not.
Are you leaving next weekend? I could./I may not./I might not.

9. Modals of Future Possibility:
Meaning and Use
 Expressing Future Possibility with Could, Might, and May
Could, might (not), and may (not) express possibility about the future. Could
and might sometimes express more uncertainty than may.
Examples:
I could get an A or a B in the course. It depends on my final paper.
I may take history next semester. It seems like a good idea.
You can talk about future possibility and future ability together with might/may
(not) + be able to. You cannot use might/may (not) + can.
Examples:
It’s already April, but I might be able to go skiing one more time.
If I learn to speak Portuguese, I may be able to get a job in Brazil.
Wrong: If I learn to speak Portuguese, I may can get a job in Brazil.

10. Modals of Future Possibility:
Meaning and Use (cont’d)
Do not confuse may be and maybe. May be is the modal may and
the be. Maybe is an adverb. It comes at the beginning of a
sentence, and it is written as one word. Maybe can be used with
will to express future possibility.
May be (Modal + Be) Maybe (Adverb)
We may be away next week. Maybe we’ll be away next week.
Use will in yes/no questions about future possibility. You can use
might, but it will sound too formal. Do not use may.
Examples: Will he come home soon?
Might he come home soon? (too formal)
Wrong: May he come home soon?