Verbos modales

Can y could

Usamos can:

• para expresar habilidad en el presente.

George can speak four languages.

Can you play any musical instruments?

• para expresar posibilidad e imposibilidad.

Where can you buy the paper?

I can’t go out tonight. I have to study.

• para pedir algo.

Can you help me?

• para pedir y dar permiso.

‘Teacher, can I go now?’ - ‘Yes, you can.’

Teenagers can stay up late at weekends if their parents agree.

Usamos can’t:

• para expresar prohibiciones.

You can’t listen to music in the library.

• para expresar una deducción negativa o cuando creemos que algo probablemente no es cierto.

He can’t be a doctor. He’s too young.

That can’t be Sheila over there. She left for Manchester yesterday.

• para hablar sobre imposibilidad en el pasado. En este caso usamos can’t + have + participio de pasado.

He can’t have been at home yesterday because I phoned him several times.

Forma

can/can’t + infinitivo sin to

!Atencion!

I can to swim.(mal) I can swim. (bien)

Could

Usamos could:

• para expresar habilidad en el pasado.

My daughter could read when she was four.

• para pedir algo de manera educada.

Could I use your phone, Mr Harris?

• para expresar permiso en el pasado.

When I was young I couldn’t stay out late at weekends.

• para hacer deducciones cuando no estamos seguros de que algo sea cierto.

I’m not sure, but that could be Tom’s mother.

• Usamos couldn’t para expresar imposibilidad en el pasado. En este caso, usamos couldn’t + have + participio de pasado.

He couldn’t have won the cookery competition: he doesn’t know how to cook.

He couldn’t have written that story so quickly.

Was/were able to

• Usamos was/were able to para expresar que teníamos la habilidad de hacer algo en una situación concreta del pasado.

Last year, I was able to run the 100 metres in under eleven seconds.

(= Corri los 100 metros en menos de once segundos.)

Was/were allowed to

• Usamos was/were allowed to para expresar permiso en el pasado.

When I was young, I was allowed to stay out late at weekends.

• Podemos usar was/were allowed to para expresar que teníamos permiso para hacer algo en el pasado en una situación concreta.

We were allowed to take photographs in the museum. (= Podiamos hacer fotografias en el museo.)

Forma

could/couldn’t + infinitivo sin to

was/were (not) + able to + infinitivo sin to

was/were (not) + allowed to + infinitivo sin to

Be able to

• can y could son las formas de presente y pasado (could también puede ser condicional). Cuando tenemos que usar otras formas verbales para hablar sobre habilidad y posibilidad, usamos be able to.

Formas de futuro: I won’t be able to do it if you don’t help me.

Formas perfectas: Have you been able to finish your essay?

!Atencion!

You will can speak English if you follow my advice.(mal)

You will be able to speak English if you follow my advice.(bien)

May y might

Usamos may:

• para pedir y dar permiso.

‘May I go to the toilet, please?’ - ‘Yes, you may.’

Usamos may o might:

• para expresar posibilidad en el presente o el futuro, cuando no estamos seguros de si algo es o no es cierto.

The exam was very difficult. I may/might pass.

It may/might rain tomorrow.

• para expresar posibilidad en el pasado cuando no estamos seguros de si ha ocurrido algo. En este caso, usamos may/might + have + participio de pasado.

‘He didn’t have any money on him, but he still bought the watch.’ - ‘He might have used his credit card.’

Formamay/might (not) + infinitivo sin to

Must y mustn’t

Usamos must:

• para expresar obligación en el presente o el futuro. Suele implicar un juicio personal por parte del hablante.

You must give up eating sweets.

I must write to Sandra.

• para dar instrucciones.

Patients must take the medicine before meals.

• para expresar una deducción positiva cuando creemos que algo es probablemente cierto.

They must be sisters. They look exactly the same.

• para hablar sobre una posibilidad en el pasado cuando estamos seguros de lo que ha ocurrido. En este caso, usamos must + have + participio de pasado.

He’s already at home. He must have taken a taxi from the airport.

Usamos mustn’t:

• para hablar sobre prohibiciones.

You mustn’t drive after taking the tablets.

You mustn’t shout in class.

!Atencion!

You must to listen in class.(mal)

You must listen in class. (bien)

Consejo: usamos have to con:

El pasado simple: After the bomb alert, they had to leave the terminal building.

Las formas de futuro: I’ll have to go to Liz’s party if she invites me.

Las formas perfectas: I’ve had to work late all week.

Forma

must/mustn’t + infinitivo sin to

Have to y don’t have to

Usamos have to:

• para hablar sobre las obligaciones de todos los días: las actividades que forman parte de la rutina.

Teenagers have to get up early during the week.

Do you have to take the car to go to work?

• para hablar sobre obligaciones que nos imponen otros.

I have to be home by eleven at weekends.

You have to be eighteen to vote in the UK.

Usamos don’t have to:

• para decir que no existe obligación de hacer algo.

Most teenagers don’t have to get up early on Saturdays.

You don’t have to vote. Voting is not compulsory in the UK.

!Atencion!

I mustn’t get up early on Sundays.(mal)

I don’t have to get up early on Sundays.(bien)

Forma

have/has to + infinitivo sin to

don’t/doesn’t have to + infinitivo sin to

Need y needn’t

Usamos need:

• para hablar sobre necesidades.

I need to work harder to pass the exam.

Usamos needn’t o don’t/doesn’t need to:

• para expresar que no existe obligación de hacer algo.

You needn’t take the exam. Your classwork is excellent.

We don’t need to hurry. There’s plenty of time.

Usamos needn’t have + participio de pasado:

• para decir que hicimos algo en el pasado que no era necesario.

I needn’t have come to school. The teacher was ill and there were no lessons.

Usamos didn’t need to:

• para expresar que no era necesario hacer algo.

We didn’t need to wait. There was no queue.

Forma

need/needn’t + infinitivo sin to

don’t need + to + infinitivo sin to

Should

Usamos should:

• para dar consejo.

You should sleep more. You look tired.

You shouldn’t eat so many sweets.

• para hablar sobre obligaciones morales.Children should look after their parents when they are old.

Formashould/shouldn’t + infinitivo sin to

Ought to

Usamos ought to:

• para dar consejo.

You ought to go to the doctor.

Consejo: ought to no es tan frecuente como should y normalmente no lo usamos en la forma negativa o en interrogativas.

• para expresar una crítica de las acciones pasadas. En este caso, usamos should/ought to + have + participio de pasado.

He ought to/should have studied more for the exam.

Formaought to/ought not to + infinitivo sin to

Ejercicios

A. Choose the correct options to complete the sentences (ability and permission.

1) Tibisay loves computers. She ……………………… tell you all about them

a. was able to

b. can

c. may

2) She learnt C++ so she ……………………… write her own programs

a. can

b. could

c. will be able to

3) She ……………………… design web pages for three months

a. can

b. is able to

c. has been able to

4) When she´s fully trained, she ……………………… get a job as a programmer

a. will be able to

b. could

c. can be able to

5) Maybe she ……………………… get a job as a web designer next year

a. was able to

b. will be able to

c. has been able to

A. Las respuestas correctas.

1) Tibisay loves computers. She can tell you all about them.

2) She learnt C++ so she can write her own programs.

3) She has been able to design web pages for three months.

4) When she´s fully trained, she could get a job as a programmer.

5) Maybe she will be able to get a job as a web designer next year.

B. Write questions using the prompts (ability and permission).

1) I´m hungry. Can / have / something to eat.

………………………………………………………………………………………………………………………………………………………………………………………………………….

2) It´s cold in here. May / close / the window

3) You have an exam tomorrow. Be able to / pass / it

4) There´s programming course next week. Could / register / for it

5) I want my teacher to repeat an explanation. Could / repeat / that / please

6) I want to go to the cinema during the week. May / go / cinema / Tuesday

B. Las respuestas correctas.

1) I´m hungry. Can / have / something to eat.

Can I have something to eat?

2) It´s cold in here. May / close / the window

May I close the window?

3) You have an exam tomorrow. Be able to / pass / it

Will you be able to pass it?

4) There´s programming course next week. Could / register / for it

Could you register for it?

5) I want my teacher to repeat an explanation. Could / repeat / that / please

Could you repeat that, please?

6) I want to go to the cinema during the week. May / go / cinema / Tuesday

May I go to the cinema on Tuesday?

C. Choose the correct options to complete the sentences (possibility and certainly)

Look at this iPad. Who owns it?

1) It isn´t mine. It (could / can´t) be Eli´s. She had one in class today.

2) No, it (must / can´t) be hers. Hers is bright pink.

3) That´s right. It (can´t / may) be Jordan´s.

4) Yes, it (might / can´t) be his

5) It (could / must) be his. He wasn´t connected to Messenger last night and he´s always connected! Let´s call him.

C. Las respuestas correctas.

1) It isn´t mine. It could be Eli´s. She had one in class today.

2) No, it can´t be hers. Hers is bright pink.

3) That´s right. It may be Jordan´s.

4) Yes, it might be his

5) It must be his. He wasn´t connected to Messenger last night and he´s always connected! Let´s call him.

D. Choose the option that explains the sentence.

1) You can´t find your keys

a. You must have left them at home

b. You must leave them at home

2) You see a couple who look very happy

a. They must have had an argument

b. They can´t have had an argument

3) You arrived late for class again

a. You shouldn´t have remembered to set the alarm clock

b. You should have remembered to set the alarm clock

4) You see your friend walking on crutches. You don´t know why.

a. He shouldn´t have broken his leg playing football.

b. He might have broken his leg playing football

D. Las respuestas correctas.

1) You can´t find your keys

a. You must have left them at home

2) You see a couple who look very happy

b. They can´t have had an argument

3) You arrived late for class again

b. You should have remembered to set the alarm clock

4) You see your friend walking on crutches. You don´t know why.

b. He might have broken his leg playing football

E. Circle the correct word

1) Don´t drink that! It (can´t / might) be dangerous!

2) He (could / must) be at home today, but I´m not sure.

3) Rosie (can´t / might not) run the race today – she´s got a broken leg

4) You (might not / could) enjoy your Saturday job, but you need to save some money.

5) We (might / can´t) go to the beach if it stops raining

6) It (can´t / might) be easy to sail around the world

E. Las respuestas correctas.

1) Don´t drink that! It might be dangerous!

2) He could be at home today, but I´m not sure.

3) Rosie can´t run the race today – she´s got a broken leg.

4) You might not enjoy your Saturday job, but you need to save some money.

5) We might go to the beach if it stops raining.

6) It can´t be easy to sail around the world.

F. Complete the sentences. Use can could, has to / have to and had to

1) a. What´s wrong? b. Sorry, I …………………….. to sit down because I´m feeling dizzy.

2) A week ago I …………………….. understand this, but now I can´t

3) Everyone …………………….. drink water to survive

4) My brother is fast. He …………………….. run 100 m in less than twelve seconds.

5) When I broke my arm, I …………………….. write with my left hand.

6) My sister …………………….. walk when she was 9 months old.

F. Las respuestas correctas.

1) a. What´s wrong? b. Sorry, I have to sit down because I´m feeling dizzy.

2) A week ago I could understand this, but now I can´t.

3) Everyone has to drink water to survive.

4) My brother is fast. He can run 100 m in less than twelve seconds.

5) When I broke my arm, I have to write with my left hand.

6) My sister could walk when she was 9 months old.

G. Complete the sentences. Use need to, needn´t, ought to or ought not to.

1) Jenna …………………….. practice so much. She is good enough.

2) The producer might have forgotten. I think Ron …………………….. call him.

3) They …………………….. film it now, tomorrow´s fine.

4) You …………………….. press this button to record.

5) He run out of money. He …………………….. find some acting work.

6) Oh, dear. What´s happened? You really …………………….. have a haircut.

7) Hey, you …………………….. copy that DVD. It might be illegal.

G. Las respuestas correctas.

1) Jenna needn´t practice so much. She is good enough.

2) The producer might have forgotten. I think Ron needs to call him.

3) They needn´t film it now, tomorrow´s fine.

4) You need press this button to record.

5) He run out of money. He ought to find some acting work.

6) Oh, dear. What´s happened? You really need have a haircut.

7) Hey, you ought not to copy that DVD. It might be illegal.

8) Do we need go to the Studio today?

H. Complete the sentences. Use the correct alternatives.

1) Andy´s missed the start of his favourite programme.

He …………………….. left work earlier.

a. may have

b. must have

c. should have

2) Oh no! The tickets aren´t in my pocket.

You …………………….. dropped them.

a. might have

b. shouldn´t have

c. should have

3) Someone rang when you were out. I don´t know who it was.

It …………………….. been the TV company.

a. may have

b. should have

c. must have

4) I missed the last episode of “The Clients List”.

Oh dear, I …………………….. recorded it for you.

a. must have

b. could have

c. shouldn’t have

5) I didn´t hear my alarm clock this morning.

You …………………….. gone to that party last night

a. shouldn´t have

b. could have

c. should have

6) I appeared on a chat show last week

You …………………….. been very nervous

a. must have

b. shouldn´t have

c. should have

H. Las respuestas correctas.

1) Andy´s missed the start of his favourite programme.

He should have left work earlier.

2) Oh no! The tickets aren´t in my pocket.

You might have dropped them.

3) Someone rang when you were out. I don´t know who it was.

It may have been the TV company.

4) I missed the last episode of “The Clients List”.

Oh dear, I could have recorded it for you.

5) I didn´t hear my alarm clock this morning.

You shouldn´t have gone to that party last night.

6) I appeared on a chat show last week

You must have been very nervous.

I. Choose the correct verb in each sentence (speculation and deduction)

1) You (can´t / mustn´t / may) be Saida´s brother- You look nothing like her.

2) I (couldn´t / must / may) phone you this evening if I have time

3) I´m never wrong about anything, so I (must / can´t / may) be right.

4) This (can / may / must) be my composition – this is my handwriting

I. Las respuestas correctas.

1) You can´t be Saida´s brother- You look nothing like her.

2) I may phone you this evening if I have time.

3) I´m never wrong about anything, so I must be right.

4) This must be my composition – this is my handwriting.

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