Modals Verbs

Modal Verbs and their substitutes

Modal verbs are for example may, can, must, should, need. They express an ability, permission, wish etc. to do something. (I may, can, must swim.) Many modal verbs cannot be used in all of the English tenses. That's why we need to know the substitutes to these modal verbs.

Modal Verb	Substitute	Example
must	to have to	I must swim. = I have to swim.
must not	not to be allowed to	I must not swim. = I am not allowed to swim.
can	to be able to	I can swim. = I am able to swim.
may	to be allowed to	I may swim. = I am allowed to swim.
need	to have to	I need to swim. = I have to swim.
need not	not to have to	I need not swim. = I don't have to swim.
shall / should/ ought to	to be supposed to / to be expected to / to be to	I shall / should / ought to swim. = I am supposed to swim. / I am expected to swim. / I am to swim.

Modal Verbs - Can

El verbo 'Can' pertenece a los verbos modales y se ubica antes del verbo principal en infinitivo. Significa 'poder'. Se utiliza para expresar habilidad, permiso.

I can - puedo

Affirmative

• I can play the trumpet.
  Yo puedo/sé tocar la trompeta.
• We can take a taxi to the airport.
  Podemos tomar un taxi hasta el aeropuerto.
• Mary can be very stubborn sometimes.
  Mary puede ser muy terca a veces.
• You can sit here if you like.
  Puedes sentarte aquí si quieres.
• It can take longer than we thought.
  (Esto) Puede tardar más de lo que pensábamos.
• Nobody can understand that.
  Nadie puede entender eso.
• Your decision can change our lives.
  Tu decisión puede cambiarnos la vida.

 

Negative

• I can not swim.
  No puedo/sé nadar.
• That cannot be true.
  Eso no puede ser cierto.
• You can't tell me what to do.
  No puedes decirme qué hacer 

Interrogative

• Can Peter speak German?
  ¿Puede/sabe Peter hablar alemán?
• Can you help me with my homework?
  ¿Me puedes ayudar con mi tarea?

 

Can + have

• Paul can have gone to Maria's.
  Paul puede haber ido a lo de María.
• They can't have left without us.
  Ellos no pueden haberse ido sin nosotros.
• Jane can't have said that.
  Jane no puede haber dicho eso.

 

Modal Verbs - Could

El verbo 'Could' Expresa poca probabilidad o condicionalidad. Significa: podría, pude, podía, pudiera de acuerdo con el contexto: I could dance if I could practice.

I could - podría / pude / podía / pudiera

 

Affirmative

• You could be wrong.
  Podrías estar equivocado.
• They could manage without us.
  Ellos pudieron/podrían arreglárselas sin nosotros.
• I could help Ann if she only let me.
  Yo podría ayudar a Ann si tan solo me dejara.
• This new plan could be very risky.
  Este nuevo plan podría ser muy riesgoso.
• The news could kill Mr. Taylor.
  La noticia podría matarlo al señor Taylor.
• Anybody could be chosen for the job.
  Cualquiera podría ser elegido para el trabajo.
• I could go back and bring Kate with me.
  Yo podría/pude volver y traer a Kate conmigo.

 

Negative

• I couldn't see very clearly.
  Yo no pude/podría ver muy claramente.
• Mrs. Jones couldn't stand the smell.
  La señora Jones no pudo/podría soportar el olor.
• We couldn't leave you alone.
  No podríamos dejarte solo. 

Interrogative

• Could you open the window?
  ¿Pudiste/podrías abrir la ventana?
• Could they escape?
  ¿Pudieron/podrían escapar?

Could + have

• You could have told me you weren't at home!
  ¡Podrías haberme dicho que no estabas en casa!
• It could have been worse.
  Pudo/podría haber sido peor.
• John couldn't have done that.
  John no pudo/podría haber hecho eso. 

Modal Verbs - May

El verbo 'may' se utiliza para expresar cierto grado de probabilidad de una acción o grado de certeza: It may rain today. Significa: podría, quizás, puede que.

I may - podría / quizás / puede que

Affirmative

• We may stay here for the night.
  Podríamos pasar la noche aquí.
• Jack may be telling the truth.
  Puede que Jack esté diciendo la verdad.
• You may ask three questions.
  Puedes hacer tres preguntas.
• I may visit Susan on Monday.
  Quizás la visite a Susan el lunes.
• The road may be blocked.
  El camino podría estar bloqueado.
• That may be a good idea.
  (Esa) Quizá sea una buena idea.
• Carol may go when she finishes.
  Carol puede/podrá ir cuando termine.

Negative

• Mr. Johnson may not remember anything.
  Puede que el señor Johnson no recuerde nada.
• You may not leave the classroom without permission.
  Usted no puede salir del aula sin permiso.
• I may not come next week.
  Quizá no venga la semana que viene. 

Interrogative

• May I go to the bathroom?
  ¿Puedo ir al baño?
• May you take this to Mr. Richards?
  ¿Podrías llevarle esto al señor Richards? 

 

May + have

• Vicky may have told me.
  Puede que Vicky me haya dicho.
• They may not have known that.
  Puede que ellos no hayan sabido eso.
• I may have forgotten to lock the door.
  Quizá me haya olvidado de cerrar la puerta con llave.

 

Modal Verbs - Might

El verbo 'might' expresa débil probabilidad o posibilidad. Se utiliza cuando queremos decir: podría, quizás, puede que (They might come tomorrow).

I might - podría / quizás / puede que

Affirmative

• They might be waiting for us at the station.
  Podrían estar esperándonos en la estación.
• This might be our only chance
  Esta podría ser nuestra única oportunidad.
• I might lose my job.
  Podría perder mi trabajo.
• Harry might write soon.
  Harry podría escribir pronto.
• You might find a solution.
  Podrías encontrar una solución.
• We might be going the wrong way.
  Quizás estemos yendo en la dirección equivocada.
• I might call you tomorrow.
  Podría llamarte mañana.

 

Negative

• Sylvia might not live there anymore.
  Quizás Sylvia ya no viva más ahí.
• We might not know everything.
  Puede que no sepamos todo.
• It might not rain tonight.
  Puede que no llueva esta noche. 

Interrogative

• Might I give you a piece of advice?
  ¿Podría darte un consejo?
• Might we speak to you for a moment?
  ¿Podríamos hablar contigo un momento? 

 

Might + have

• They might have finished earlier.
  Quizás hayan terminado más temprano.
• Bob might have died in the accident.
  Bob podría haber muerto en el accidente.
• Miss Green might not have been present at the time.
  Puede que la señorita Green no haya estado presente en ese momento.

Modal Verbs - Must

El verbo 'must' expresa una prohibición u obligación fuerte así como cierta certeza: I must go. She must be crazy. En español significa debo, debo de.

I must - debo / debo de

Affirmative

• I must go to the library.
  Debo ir a la biblioteca.
• You must stay here until I come back.
  Debes quedarte aquí hasta que yo vuelva.
• We must be at the airport at three o'clock.
  Debemos estar en el aeropuerto a las tres.
• Everybody must wear a uniform.
  Todos deben usar uniforme.
• You must be joking!
  ¡Deben de estar bromeando!
• Julia must be in Paris by now.
  Julia ya debe de estar en París.
• It must be noon already.
  Ya debe de ser mediodía.

 

Negative

• You must not talk to strangers.
  No debes hablar con extraños.
• We mustn't make noise.
  No debemos hacer ruido.
• Mr. Williams must not smoke.
  El señor Williams no debe fumar. 

 

Interrogative

• Must we do everything today?
  ¿Debemos hacer todo hoy?
• Must you go so soon?
  ¿Debes irte tan pronto? 

 

Must + have

• I must have fallen asleep.
  Debo de haberme quedado dormido.
• Sally must have forgotten about the meeting.
  Sally debe de haberse olvidado de la reunión.
• They must have sent it already.
  Ya deben de haberlo enviado. 

Modal Verbs - Should

Usamos 'should' para expresar grado de posibilidad o probabilidad, así como también para obligación débil. Significa: debería, tendría que. I should study.

I should - debería / tendría que

Affirmative

• You should tell Miss Baker the truth.
  Deberías decirle la verdad a la señorita Baker.
• We should go to sleep.
  Deberíamos ir a dormir.
• I should call my mother.
  Debería llamar a mi madre.
• They should leave as soon as possible.
  Ellos deberían salir lo antes posible.
• She should be doing her homework.
  Ella debería estar haciendo su tarea.
• Ben should exercise more.
  Ben debería ejercitarse más.
• It should be here.
  (Esto) Debería estar aquí. 

 

Negative

• You should not say that.
  No deberías decir eso.
• Nick shouldn't be working.
  Nick no debería estar trabajando.
• It shouldn't take long.
  (Esto) No debería tardar mucho. 

 

Interrogative

• Should I write Maggie a letter?
  ¿Debería yo escribirle una carta a Maggie?
• Should we worry?
  ¿Deberíamos preocuparnos? 

Should + have

• Charlie should have consulted me.
  Charlie debería haberme consultado.
• I shouldn't have eaten so much.
  Yo no debería haber comido tanto.
• Danny and Paul should have waited for you.
  Danny y Paul deberían haberte esperado. 

Modal Verbs - Ought to

El verbo 'ought to' es igual al 'should' y expresa una obligación débil. Significa debería, tendría que.

I ought to - debería / tendría que

 

Affirmative

• Helen ought to be more careful.
  Helen debería tener más cuidado.
• I ought to stay in bed.
  Yo debería quedarme en la cama.
• We ought to go together.
  Deberíamos ir juntos.
• They ought to be here already.
  Ellos ya deberían estar aquí.
• You ought to eat more vegetables.
  Deberías comer más vegetales.
• Tom ought to take her home.
  Tom debería llevarla a casa.
• It ought to work properly.
  (Esto) Debería funcionar correctamente. 

Negative

• You ought not to drink so much.
  No deberías beber tanto.
• They ought not to go camping without a torch.
  Ellos no deberían ir de camping sin una linterna.
• George ought not to wear someone else's glasses.
  George no debería usar los anteojos de otra persona. 

 

Interrogative

• Ought Rachel to be here so early?
  ¿Debería Rachel estar aquí tan temprano?
• Ought they to live there?
  ¿Deberían ellos vivir allí? 

 

Ought to + have

• You ought to have read the book for today.
  Deberían haber leído el libro para hoy.
• They ought to have gone to the supermarket.
  Ellos deberían haber ido al supermercado.
• We ought to have listened to the guard.
  Deberíamos haber escuchado al guardia. 

Modal verbs

The modal verbs include can, must, may, might, will, would, should. They are used with other verbs to express ability, obligation, possibility, and so on. Below is a list showing the most useful modals and their most common meanings:

Modal	Meaning	Example
can	to express ability	I can speak a little Russian.
can	to request permission	Can I open the window?
may	to express possibility	I may be home late.
may	to request permission	May I sit down, please?
must	to express obligation	I must go now.
must	to express strong belief	She must be over 90 years old.
should	to give advice	You should stop smoking.
would	to request or offer	Would you like a cup of tea?
would	in if-sentences	If I were you, I would say sorry.

Modal verbs are unlike other verbs. They do not change their form (spelling) and they have no infinitive or participle (past/present). The modals must and can need substitute verbs to express obligation or ability in the different tenses. Here are some examples:

Past simple	Sorry I'm late. I had to finish my math test.
Present perfect	She's had to return to Korea at short notice.
Future	You'll have to work hard if you want to pass the exams.
Infinitive	I don't want to have to go.

Past simple	I couldn't/wasn't able to walk until I was 3 years old.
Present perfect	I haven't been able to solve this problem. Can you help?
Future	I'm not sure if I will be able to come to your party.
Infinitive	I would love to be able to play the piano.

Modals are auxiliary verbs. They do not need an additional auxiliary in negatives or questions. For example: Must I come? (Do I must come?), or: He shouldn't smoke (He doesn't should smoke).

Modals are different from normal verbs:

1: They don't use an 's' for the third person singular.
2: They make questions by inversion ('she can go' becomes 'can she go?').
3: They are followed directly by the infinitive of another verb (without 'to').

Probability:

First, they can be used when we want to say how sure we are that something happened / is happening / will happen. We often call these 'modals of deduction' or 'speculation' or 'certainty' or 'probability'.
For example:

• It's snowing, so it must be very cold outside.

• I don't know where John is. He could have missed the train.

• This bill can't be right. £200 for two cups of coffee!

Modal Verbs of Probability

We can use these modal verbs (also called modals of deduction, speculation or certainty) when we want to make a guess about something. We choose the verb depending on how sure we are.

1: Talking about the present:

must / might / could / may / can't

• must + infinitive
• might / might not + infinitive
• could / could not + infinitive
• may / may not + infinitive
• can't + infinitive

For example:

I am waiting for Julie with another friend, David.
I ask: 'Where is Julie?'
David guesses:

• She must be on the bus. (I'm fairly sure this is a good guess)
• She might come soon. (maybe)
• She could be lost. (maybe)
• She may be in the wrong room. (maybe)
• She can't be at home. (I'm fairly sure this isn't true)

Notice that the opposite of 'must' is 'can't in this case.

Will / won't

We use will and won't when we are very sure:

• She'll be at work now.

Should / shouldn't

Should and shouldn't are used to make an assumption about what is probably true, if everything is as we expect:

• They should be there by now.
• It shouldn't take long to drive here.

This use of should isn't usually used for negative events. Instead, it's a better idea to use will:

• The underground will be very busy now (not: 'should be').

Can

Can is used for something that is generally possible, something we know sometimes happens:

• Prices can be high in London.

Can is not used to talk about specific possibilities:

• He could be on the bus (not: 'can be').

2: Using modal verbs to talk about the past:

must / might / could / may / can't + have + past participle

(Click here to review how to make the past participle)

• must have + past participle
• might / might not have + past participle
• could / couldn't have + past participle
• may / may not have + past participle
• can't have + past participle

For example:

You: Where was Julie last night?
David:

• She must have forgotten about our date.
• She might have worked late.
• She could have taken the wrong bus.
• She may have felt ill.
• She can't have stayed at home.

Will / won't + have + past participle

Will and won't / will not + have + past participle are used for past certainty (compare with present use of 'will' above):

• The parcel will have arrived before now.

Should + have + past participle

Should + have + past participle can be used to make an assumption about something that has probably happened, if everything is as we expect (compare with present use of 'should' above):

• The train should have left by now

Could

We can use could + infinitive to talk about a general possibility in the past (compare with the use of 'can' above):

• Prices could be high in the sixteenth century.

This is not used to talk about specific possibilites in the past (instead we use could + have + past participle):

• He could have been working late (not: 'could be'. As this is a specific possiblity, 'could be' is present tense)

Ability

We use 'can' and 'could' to talk about a skill or ability.

For example:

• She can speak six languages.
• My grandfather could play golf very well.
• I can't drive.

When we talk about ability, we mean two things.

First, we mean general ability. This is something that once you have learned you can do any time you want, like being able to read or swim or speak a language, for example.

The other kind of ability is specific ability. This mean something that you can or can't do in one particular situation. For example, being able to lift something heavy, or find somewhere you are looking for.

Present:

can / can't (for both general and specific ability)

• I can play the piano.
• She can speak English.
• He can't drive – he's too tired.
• We can't come now.

Past:

could / couldn't (for general ability)

• I could read when I was four.
• She could speak French when she was a child, but now she has forgotten it.
• He couldn't dance at all until he took lessons.
• My grandfather couldn't swim.

was able to / couldn't (for specific ability)

• When the computer crashed yesterday, I was able to fix it.(not 'I could fix it')
• She was able to pass the exam, even though she hadn't studied much.(not 'she could pass')
• He called us because he couldn't find the house.
• I couldn't open the window.

could + have + past participle (an ability someone had in the past, but didn't use)

• I could have played the piano well but I didn't practise enough.
• We could have come earlier.
• She could have studied law, but she preferred to become a secretary.

Future:

will / won't be able to (general ability)

• At the end of the course, you will be able to make your own website.
• He won't be able to speak Japanese in a week! It will take months.

can / can't (specific ability)

• I can help you tomorrow
• I can't come to the party

Obligation and Advice

We can use verbs such as 'must' or 'should' to say when something is necessary or unnecessary, or to give advice.

For example:

• Children must do their homework.
• We have to wear a uniform at work.
• You should stop smoking.

We can use have to + infinitive, must + infinitive and should + infinitive to express obligation (something you have to do).

Present	Positive	Negative
have to / don't have to	strong obligation (possibly from outside) Children have to go to school. (sometimes 'have got to')	no obligation I don't have to work on Sundays. You don't have to eat anything you don't like.
must / mustn't	strong obligation (possibly based on the speaker's opinion) I must study today.	negative obligation You mustn't smoke here.
should / shouldn't	mild obligation or advice You should save some money.	mild negative obligation or advice You shouldn't smoke so much.

Be careful about the difference between mustn't and don't have to!
Mustn't means it's not allowed, or it's a bad idea:

• You mustn't eat so much chocolate, you'll be sick

Don't have to means you don't need to do something, but it's fine if you want to do it:

• I don't have to get up early at the weekend(of course, if I want to get up early, that's fine, but I can stay in bed if I want).

Past	Positive	Negative
had to / didn't have to	obligation in the past I had to wear a school uniform when I was a child.	no obligation in the past We didn't have to go to school on Saturdays.
must*	changes to 'had to'	-
should have + pp / shouldn't have + pp	a past action which didn't happen: the advice / regret is too late You should have gone to bed earlier, now you have missed the train.	a past action which didn't happen: the advice / regret is too late You shouldn't have taken that job., it was a bad idea.

* Remember 'must have done' is a modal verb of deduction or speculation, not obligation in the past. For example: Julie must have left. Her coat's not here. 

Permission

We can use verbs such as 'can', 'could' and 'may' to ask for and give permission. We also use modal verbs to say something is not allowed.

For example:

• Could I leave early today, please?
• You may not use the car tonight.
• Can we swim in the lake?

Habits

We can use 'will' and 'would' to talk about habits or things we usually do, or did in the past.

For example:

• When I lived in Italy, we would often eat in the restaurant next to my flat.
• John will always be late!

Past modals

The past modals 'could have + past participle', 'should have + past participle' and 'would have + past participle' can be confusing.

Could have, should have, would have

These past modal verbs are all used hypothetically, to talk about things that didn't really happen in the past.

Could have + past participle

1: Could have + past participle means that something was possible in the past, or you had the ability to do something in the past, but that you didn't do it. 

I could have stayed up late, but I decided to go to bed early.

• They could have won the race, but they didn't try hard enough.
• Julie could have bought the book, but she borrowed it from the library instead.
• He could have studied harder, but he was too lazy and that's why he failed the exam.

Couldn't have + past participle means that something wasn't possible in the past, even if you had wanted to do it.

• I couldn't have arrived any earlier. There was a terrible traffic jam (= it was impossible for me to have arrived any earlier).
• He couldn't have passed the exam, even if he had studied harder. It's a really, really difficult exam.

2: We use could have + past participle when we want to make a guess about something that happened in the past. In this case, we don't know if what we're saying is true or not true. We're just talking about our opinion of what maybe happened.

Why is John late?

• He could have got stuck in traffic.
• He could have forgotten that we were meeting today.
• He could have overslept.

We can also choose to use might have + past participle to mean the same thing:

• He might have got stuck in traffic.
• He might have forgotten that we were meeting today.
• He might have got stuck in traffic.

Should have + past participle

1: Should have + past participle can mean something that would have been a good idea, but that you didn't do it. It's like giving advice about the past when you say it to someone else, or regretting what you did or didn't do when you're talking about yourself.

Shouldn't have + past participle means that something wasn't a good idea, but you did it anyway.

• I should have studied harder! (= I didn't study very hard and so I failed the exam. I'm sorry about this now.)
• I should have gone to bed early (= I didn't go to bed early and now I'm tired).
• I shouldn't have eaten so much cake! (= I did eat a lot of cake and now I don't feel good.)
• You should have called me when you arrived (= you didn't call me and I was worried. I wish that you had called me).
• John should have left early, then he wouldn't have missed the plane (= but he didn't leave early and so he did miss the plane).

2: We can also use should have + past participle to talk about something that, if everything is normal and okay, we think has already happened. But we're not certain that everything is fine, so we use 'should have' and not the present perfect or past simple. It's often used with 'by now'.

• His plane should have arrived by now (= if everything is fine, the plane has arrived).
• John should have finished work by now (= if everything is normal, John has finished work).

We can also use this to talk about something that would have happened if everything was fine, but hasn't happened.

• Lucy should have arrived by now, but she hasn't.

Would have + past participle

1: Part of the third conditional.

• If I had had enough money, I would have bought a car (but I didn't have enough money, so I didn't buy a car).

The Third Conditional

We make the third conditional by using the past perfect after 'if' and then 'would have' and thepast participle in the second part of the sentence:

• if + past perfect, ...would + have + past participle

It talks about the past. It's used to describe a situation that didn't happen, and to imagine the result of this situation.

• If she had studied, she would have passed the exam (but, really we know she didn't study and so she didn't pass)
• If I hadn't eaten so much, I wouldn't have felt sick (but I did eat a lot, and so I did feel sick).
• If we had taken a taxi, we wouldn't have missed the plane
• She wouldn't have been tired if she had gone to bed earlier
• She would have become a teacher if she had gone to university
• He would have been on time for the interview if he had left the house at nine

2: Because 'would' (and will) can also be used to show if you want to do something or not (volition), we can also use would have + past participle to talk about something you wanted to do but didn't. This is very similar to the third conditional, but we don't need an 'if clause'.

• I would have gone to the party, but I was really busy.
  (= I wanted to go to the party, but I didn't because I was busy. If I hadn't been so busy, I would have gone to the party.)

• I would have called you, but I didn't know your number.
  (= I wanted to call you but I didn't know your number, so I didn't call you.)

• A: Nobody volunteered to help us with the fair
  B: I would have helped you. I didn't know you needed help.
  (= If I had known that you needed help, I would have helped you.)

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MODALS VERBS 

Modal Verb Tutorial