Lesson 19. Modal Verbs

Grammar Focus: Modal Verbs

Modal verbs are special helping verbs. They add meanings such as ability, possibility, permission, obligation, advice, certainty, prediction, or willingness to another verb.

Common modal verbs include:

can, could, may, might, must, shall, should, will, would

How Modal Verbs Work

Most modal verbs follow the same basic pattern:

subject + modal verb + base form of the verb

Important Rules

Modal verbs are different from ordinary verbs in several ways.

• Do not add an s in the third-person. Example: He can swim.
• Do not use do or does when making questions. Example: Can you help me?
• For the negative form, put not after the modal verb. Example: I should not go.
• Do not use to after a modal verb. Example: She must leave.
• They do not have an infinitive form.
• They do not have all the forms of ordinary verbs.

The following sections will discuss each of the modal verbs.

Can

The modal verb can is very common and means either to have the ability to do something or to have permission to do something.

1. Ability

We use can to say that someone has the ability to do something.

Form:

subject + can + base verb

Examples	Español
I can speak English.	Puedo hablar inglés.
She can swim across the lake.	Ella puede nadar hasta el otro lado del lago.

Questions

To form a question, put the subject of the sentence after can.

Examples	Español
Can she swim?	¿Puede nadar?
Can you speak English?	¿Puedes hablar inglés?

Negative

To form a negative statement, use cannot or its common contraction can't.

Examples	Español
She cannot swim.	Ella no puede nadar.
I can't drive.	No sé conducir / No puedo conducir.

2. Permission

Can is also used to ask for or give permission.

Examples	Español
Can I open the window?	¿Puedo abrir la ventana?
You can leave early today.	Puedes irte temprano hoy.

Could

The modal verb could has several important meanings.

1. Past Ability

Could is the simple past of can and is used for general abilities in the past.

Examples	Español
She could swim across the lake before she broke her leg.	Ella podía nadar a través del lago antes de que se rompiera la pierna.
I could swim when I was five.	Sabía nadar cuando tenía cinco años.
She could speak French when she was a child.	Ella sabía hablar francés cuando era niña.

2. Possibility

Could is used to say that something is possible.

Examples	Español
She could swim across the lake if she wanted to.	Ella podría nadar a través del lago si quisiera.
It could rain tomorrow.	Podría llover mañana.
We could miss the train.	Podríamos perder el tren.

3. Polite Requests

Could is used very often to make polite requests.

Examples	Español
Could you help me?	¿Podrías ayudarme?
Could you open the door?	¿Podrías abrir la puerta?

4. Hypothetical Situations

Could is also used to talk about an ability or possibility that depends on one or more conditions.

Examples	Español
I could help you if I had more time.	Podría ayudarte si tuviera más tiempo.
We could go to the beach if the weather improved.	Podríamos ir a la playa si mejorara el tiempo.

Could Have

Could have + past participle is used to talk about a possibility or opportunity in the past. Could have is often shortened to could've.

Examples	Español
She could have won the race.	Podría haber ganado la carrera.
We could have gone to the concert.	Podríamos haber ido al concierto.
Could she have swum across the lake?	¿Podría haber nadado a través del lago?
She could've swum across the lake if she'd wanted to.	Ella podría haber nadado a través del lago si hubiera querido hacerlo.
She could have taken the earlier train.	Podría haber tomado el tren anterior.
They could have forgotten about the meeting.	Podrían haberse olvidado de la reunión.

Forms of Can / Be Able

Unlike most verbs Can only has a present and a past tense. For other forms, be able is used. The following table shows the different forms that are used.

May

Possibility

May and might are both commonly used when something is possible but uncertain.

Examples	Español
John may have an extra pen.	John puede tener un bolígrafo extra.
I may go to the concert.	Puede que vaya al concierto.
I may not have time to eat dinner.	Puede que no tenga tiempo para cenar.
She may be able to help you.	Puede que ella pueda ayudarle.
It might happen.	Puede que suceda.
I might not be able to do it.	Puede que no pueda hacerlo.

Permission

May can also be used to ask for or give permission, especially in more formal situations. In informal situations, can is more commonly used to ask for or give permission.

Examples	Español
May I go to the store?	¿Puedo ir a la tienda?
May I have something to drink?	¿Puedo tomar algo para beber?
You may have one chocolate bar.	Puede tomar una barra de chocolate.

May Have and Might Have

May have + past participle and might have + past participle are both used to indicate that an event possibly happened in the past. Might have is often shortened to might've.

Examples	Español
It might have happened.	Puede que haya pasado.
I may have lost the keys.	Puede que haya perdido las llaves.

Must and Have to

1. Obligation

Must and have to can both express strong obligation.

Examples	Español
You must wear a seat belt.	Debes llevar puesto el cinturón de seguridad.
I have to work tomorrow.	Tengo que trabajar mañana.
She has to pass the exam.	Tiene que aprobar el examen.
She must pass the exam, or she will fail the course.	Ella debe aprobar el examen, o suspenderá el curso.

Must is only used in the present tense. Have to is especially useful because it can change form for different grammatical contexts.

Form	Expression
Infinitive	to have to
Present	must / have to
Past	had to
Present perfect	have had to
Past perfect	had had to
Conditional	would have to
Future	will have to

Examples	Español
She had to leave early.	Tuvo que irse temprano.
I'll have to do it eventually.	Tendré que hacerlo tarde o temprano.
She had to pass the exam to be able to pass the course.	Ella tuvo que aprobar el examen para poder aprobar el curso.

2. Must for Strong Deductions

Must does not always express obligation. It can also express a strong conclusion based on what we know or observe.

3. Must Not and Don't Have To

Must not and don't have to have very different meanings.

Examples	Español
We've been walking for two hours. We must be near the lake.	Llevamos dos horas caminando. Debemos de estar cerca del lago.
He must be almost at the lake by now.	Debe de estar casi en el lago ahora mismo.
I must be going too slow.	Debo de estar yendo demasiado lento.

Must Not = Prohibition

Use must not or mustn't when an action is not allowed or it is very important not to do something.

Examples	Español
You mustn't leave.	No debes irte.
You mustn't bring food into the library.	No debes llevar comida a la biblioteca.
We must not forget to lock the door when we leave.	No debemos olvidar cerrar la puerta cuando nos vayamos.

Don't Have To = No Necessity

Use don't have to when something is not necessary. You can do it, but you are not required to do it.

Examples	Español
You don't have to leave.	No tienes que irte.
I don't have to bring my laptop.	No tengo que llevar mi portátil.

Must Have

Use must have + past participle to make a strong deduction about the past.

Examples	Español
I must have left my keys at home.	Debo de haber dejado las llaves en casa.
They must have known what would happen if they did that.	Debieron de saber lo que pasaría si hacían eso.
He must've forgotten about it.	Él debió de olvidarse de eso.

Should

1. Advice and Recommendations

We commonly use should to give advice or make recommendations.

Use should + base verb. Do not use to after should.

Examples	Español
You should get more exercise.	Deberías hacer más ejercicio.
You should study more.	Deberías estudiar más.
We should see the new film.	Deberíamos ver la nueva película.

2. Asking for Advice

To ask for advice, put should before the subject.

should + subject + base verb?

Examples	Español
Should I study tonight?	¿Debería estudiar esta noche?
What should I do?	¿Qué debería hacer?
Should we leave now?	¿Deberíamos irnos ahora?

3. Negative Form: Shouldn't

Use should not or the contraction shouldn't to advise someone not to do something.

Examples	Español
You shouldn't worry.	No deberías preocuparte.
You shouldn't drive so fast.	No deberías conducir tan rápido.
We shouldn't spend so much money.	No deberíamos gastar tanto dinero.

4. Expectations

Should can also express an expectation. In this use, we are saying that we think something will probably happen or that we expect a situation to be true.

Examples	Español
The train should arrive soon.	El tren debería llegar pronto.
They should be home by now.	Ya deberían estar en casa.
The package should arrive tomorrow.	El paquete debería llegar mañana.

5. Ought To

Ought to has a meaning similar to should, especially when giving advice or talking about what is appropriate.

Examples	Español
You ought to get more sleep.	Deberías dormir más.
We ought to help them.	Deberíamos ayudarlos.

For most everyday situations, you can use should.

Shall

In everyday English, shall is most useful in questions with I and we. We commonly use it to make suggestions and offers.

Like other modal verbs, shall is followed by the base form of the verb without to.

1. Making Suggestions

Use shall we + base verb? to suggest doing something together.

Examples	Español
Shall we go?	¿Nos vamos?
Shall we start?	¿Empezamos?
Shall we eat outside?	¿Comemos fuera?
Shall we invite Marta?	¿Invitamos a Marta?

2. Making Offers

Use shall I + base verb? when you offer to do something for someone or ask whether they want you to do something.

Examples	Español
Shall I open the window?	¿Abro la ventana?
Shall I help you?	¿Te ayudo?

Note: Can I ... and Would you like me to ... are both more common ways to offer to help someone.

Will

Will + base verb is one of the most common ways to talk about the future. It expresses predictions, promises, spontaneous decisions, and things we believe will happen.

The common contraction of will after a subject is 'll.

1. Predictions and Future Events

Use will when you predict or expect something to happen in the future. Will often pairs with adverbs of probability like probably, definitely, certainly, or maybe.

Examples	Español
We will talk about it later.	Hablaremos de eso más tarde.
I'm sure it will work.	Estoy seguro de que funcionará.
He will probably arrive soon.	Probablemente él llegará pronto.
We'll have time for dinner.	Tendremos tiempo para cenar.

2. Spontaneous Decisions

Use will when deciding something at the moment of speaking.

Examples	Español
I'll get the door.	Voy a abrir la puerta.
I'll call you tomorrow.	Te llamaré mañana.
That sounds good. I'll come!	Suena bien. ¡Voy!

Offers and Promises

Will is often used when making a promise, offer, or commitment to someone.

Examples	Español
I will help you with your homework.	Te ayudaré con tu tarea.
We'll take care of everything.	Nos encargaremos de todo.

Negative Form

The negative form is will not, which is commonly contracted to won't.

Examples	Español
We won't have time for dinner.	No tendremos tiempo para cenar.
It won't work.	No funcionará.
They won't finish on time.	No terminarán a tiempo.

Questions

To form a question, put the subject of the sentence after will.

Examples	Español
Will you go shopping after work?	¿Irás de compras después del trabajo?
Will they come tomorrow?	¿Vendrán mañana?
What will you do?	¿Qué harás?

Would

Would has several important uses. The two most common are hypothetical situations and polite requests.

1. Hypothetical Situations

Use would when talking about imaginary or unlikely situations. This is often paired with an if-clause.

Would is often contracted to 'd

Examples	Español
I'd go to the concert if I had more money.	Iría al concierto si tuviera más dinero.
We would buy the house if it were cheaper.	Compraríamos la casa si fuera más barata.
She would travel more if she had vacation time.	Viajaría más si tuviera tiempo de vacaciones.
She'd help us if she could.	Nos ayudaría si pudiera.
They would help if they knew the truth.	Ellos ayudarían si supieran la verdad.
I'd learn Italian if I lived in Rome.	Aprendería italiano si viviera en Roma.

2. Polite Requests

Would is also common in polite requests.

Examples	Español
Would you help me?	¿Me ayudarías?
Would you open the window, please?	¿Abrirías la ventana, por favor?

Past Habits

Would can also describe repeated habits or actions that happened in the past but do not happen now. It has the same meaning as used to.

Examples	Español
When I was young, I would play outside every day.	Cuando era joven, jugaba afuera todos los días.
We would visit them every summer.	Los visitábamos cada verano.

Negative Form

Would not is usually contracted to wouldn't.

Examples	Español
I wouldn't do that.	Yo no haría eso.
They wouldn't agree.	No estarían de acuerdo.