Modal Verbs – Could

We use “Could” to express the following: 1) possibility, 2) ability in the past, 3) polite request, 4) as a conditional statement and 5) as a soft suggestion.

Could to Express Possibility

When we want to express a possibility that is about 50% we can also use the modal verb “could”.


She could be at home, she said she might take the day off.

They could win the game, they seem to ready for it.

It’s very bright this morning, it could be a nice day later on.

There could be some oil in that area, geologically there is potential.

She could marry him, after all he has a lot of money.

In each of the above examples there is a possibility for each of the situations to be true, but they are not certain to be true. Each statement is about a 50% possibility. This differs from the modal verb “should” which is a stronger possibility than “could” because the speaker has a stronger reason or more evidence in believing what they are saying. Compare the following examples:

It could rain today, It hasn’t rained for a while.

It should rain today, the clouds are very dark and heavy.

In the first statement the speaker is only guessing without a real strong reason. In the second statement the speaker has more evidence because he/she can see that the conditions for rain are present.

She could be at the party, she said she might go.

She should be at the party, she said she was going to go.

In the third statement the speaker is not sure because they use another modal, “might” which

indicates a possibility, but not a strong possibility. In the fourth statement the speaker is more certain that she is “at the party” because she told the speaker directly that “she was going to go to the party”.

They could be finished with their homework by now.

They should be finished with their homework by now.

Even though both statements five and six are the same, the speaker in statement six is more confident that they are finished with their homework even though no reason was given. The use of the modal “should” tells the listener the speaker is more certain.

Here are examples with the modal verb “could” as a 50% possibility.

You know, they could be at their friends’ house, they said they might go there.

I don’t know, I could pass the test but it is going to be difficult.

She could love me, she always looks at me with bright eyes and a smile.

The aliens could land here, they have the capability.

Note: The negative of “could” as a possibility is couldn’t but it is much stronger in the negative form than in the affirmative form.


It couldn’t be them already, they just left ten minutes ago.

There couldn’t be oil in this area because it’s not geologically possible.

She couldn’t love me, she’s been going out with that idiot Jose Gonzales!

The aliens couldn’t possibly land here, they can’t even drive cars!

In the above examples the speaker is very certain in each of the situations.

The speaker has strong reasons for making each of the negative statements or they feel very strongly in what they are saying.

Could to Express Ability in the Past

When we want to express someone’s ability in the past that no longer exists now we use “could”.


When I was fifteen years old I could easily swim two miles without stopping.

He could score one goal each game, but since his injury he had to quit playing soccer.

I could dance all night at the discos and still get up for class when I was twenty, but now that I am thirty I go to bed at 10:00 pm.

She could sing beautifully when she was single, but she lost her voice when she got married.

He could go out with any girl he wanted to when he was twenty, but now that he is old, bald and fat he has to beg girls to go out with him.

In each of the above examples there was some ability in the past that no longer exists now. The negative of “could” as a past ability is “couldn’t”.


He couldn’t swim well when he was young, now he is in the Olympics competing for a gold medal in every swimming event!

Thalia couldn’t sing well when she was a child but now she is one of the most popular Latin singers in the world!

My sister couldn’t do math in elementary school but now she is as good as Einstein was!

My wife couldn’t cook when we were dating, but since we’ve been married I’ve taught her everything she knows about cooking!

 I couldn’t speak English before I took this course, but now I can speak better English than the teacher!

The structure for “could” as a possibility and “could” as ability in the past is the same. We only change the complement.

Subject + Could + Verb in Infinitive Form + Complementizer
could play golf when I was young.
could paint that later.
could tell the police.
could be at the park.
could win the race.
could go to my sister’s house.
could leave tomorrow.

Could as a Polite Request

“Could” can also be used as a polite request or request for permission but more informally than “May I”. The most common usage of “could” as a polite request or request for permission is with the pronouns “I” and “you”.


Could I use your phone for a second?

Mommy, could I go outside to play?

Sir, could I see your driver’s license, registration and proof of insurance, please?

Could you please be quiet for a second, I am trying to talk to this beautiful girl.

Bill could you please get me a glass of water. I think I am going to faint.

Could I have eight hamburgers. Three colas and three orders of fries, please?

Could he please be excused from class tomorrow, his sister is getting married.

Could she live with us for a while, she is still in shock because her husband left her.

Do you think they could borrow $ 5,000 from us honey?

Could you please pass me my pen. It is under your desk.

The structure for “could” as a polite request is as follows:

Could + Subject + Verb in Infinitive Form + Complementizer
I (please) have your number?
You pass the butter (please)?
he (please) come to our house?
she (please) spend the night?
we go outside (please)?
they leave work early (please)?

Note: “Please” is optional after the pronoun or the entire request. It is not necessary but it makes the request more polite and formal. It is suggested that you use “please” whenever making a request.

 Could for Conditional Statements

When we want to express a situation that is not likely to happen at the present moment, because it depends on other events to take place, we call these situations conditionals. We often use the modals “could” and “would” to express these situations that at the present time are not likely to happen. We also have to include the word “if” when we make conditional statements.

The structure is as follows:

Subject + Could + Verb in Infinitive Form + if + Subject + Verb in Simple Past + Complementizer


I could pass the exam if I studied hard for it.

You could go dancing tonight if you felt better.

She could win the lottery if she bought a ticket.

If she got a scholarship, she could afford to go to college.

If they practiced enough, they could win the baseball tournament.

If we left early enough we could make it on time.

Note: It doesn’t matter if the “if clause” is at the beginning or in the second part of the statement.

In the first example the speaker has the possibility to pass the exam, but he / she must study hard for it.

In the second example, the speaker tells the listener that it´s possible for him to go dancing but the condition is that he / she must feel better.

In the third example, the speaker is saying that “she” has the possibility to win the lottery, but the condition is that she must buy a lottery ticket.

 In the last three examples above the statement begins with the “if” clause and the result clause follows with no change in meaning.

Here are more examples of conditional statements using “could”:

If I had enough money, I could buy a new car.

I could buy a new car if I had enough money.

I could go to the moon if I were an astronaut.

If I were an astronaut, I could go to the moon.

She could win a beauty contest if she lost some weight.

If she lost some weight, she could win a beauty contest.

Note: It is also important to note that when using the verb “to be” in conditional statements all persons are conjugated in the “were” form.


I could buy a big house if I were rich.

He could win the race if he were a little faster.

I could go to the discos if I were older but I am only twelve.

If she were smarter, she could get rid of that guy.

If I were at the party now I could be dancing with her.

It is also possible to make negative conditional statements, but we must use: couldn’t, didn’t or weren’t.


If I didn’t study English, I couldn’t go to Australia.

If he didn’t have the money, he couldn’t buy that car.

If she weren’t trained for the job, she couldn’t do the work.

They couldn’t pass the exam if they didn’t study.

If I didn’t work, I couldn’t get money.

Could as a Soft Suggestion

When we want to make a suggestion not quite as strong as “should”, we sometimes use the modal verb “could” which is similar to using “might” as a soft suggestion.


You could study a little harder.

The students could show more respect towards their teachers.

Margaret could tell her husband she loves him once in a while.

We could take more trips out of the city more often.

You could come home earlier you know.