Modal verbs / Modals

This is a practical summary of the main meanings expressed by the set of verbs generally called modal verbs or modals.

Modals can express a varied range of ideas and shades of meaning, very useful to complete the English verb conjugation system.

They are usually divided into central modals(can/could, may/might, must, shall/should, will/would) and semimodals or marginal modals (ought to, used to, need, dare).

I'll concentrate on the main meanings expressed by the central modals, though I will include some notes about the following semi-modals: ought to, as an alternative to should,needn't (the negative of need), for absence of obligation, and used to, for habitual actions in the past, as against to be used to, for sth you are accustomed to doing.

1.- CAN/MAY?

• Can indicates mainly capacity or abilility to do sth:

I’m sure he can do (it) better than that – estoy seguro de que puede hacerlo mejor.

My wife can speak French - mi mujer sabe hablar francés.

• May indicates that sth is possible:

It may rain this afternoon - puede que llueva esta tarde.

• Both can and may can be used to indicate ‘permission’, but may is more formal than can:

Can I smoke? - ¿puedo fumar? (informal)

May I smoke? - ¿puedo fumar? (formal)

Practice -1

Fill in the gaps with can or may asrequired

a.- Gwen _______ play the piano, but she __________ play the violin.

b.- He says he ______ come this weekend if he _________ find a cheap flight.

c.- __________ you walk a bit faster? We’re going to be late for the concert.

d.- The TV said that it ___________ be colder tomorrow.

e.- If there’s anything I ___________ do to help you give me a ring.

f.- Mum, __________ I borrow your necklace for Linda’s wedding?

g.- Excuse me, Madam, ___________ I use your phone?

KEY 1

a.- can; can’t; b.- may; can; c.- can; d.- may/might; e.- can; f.- can; g.- may.

2.- ‘PODER’ IN THE INFINITIVE AND FUTURE AND PERFECT TENSES

Can, like the rest of modals, is defective, lacking a toinfinitive and a participle, so to translate ‘poder’ in the infinitive, the future or perfect tenses use to be able:

• I won’t be able to come tomorrow – no podré venir mañana.
• I haven’t been able to do it – no he podido hacerlo.

Practice -2

Complete the sentences with the adequate form of to be able

a.- In fifty years’ time I’m sure that everybody ______ to live to a hundred.

b.- I have your report, but I ______________ to read it yet.

c.- I’ve always wanted ________________ to speak Japanese.

d.- Martin has just phoned to say that he ______________ to come tomorrow.

KEY 2

a.- will be able; b.- haven’t been able; c.- to be able; d- won’t be able

3.- MUST/SHOULD?

Both can mean ‘deber’, but must is always more forceful, more assertive than should, so use must for moral or legal obligation, rules, commands or strong advice:

• You must switch off your mobile phone in the cinema – debes apagar tu móvil en el cine
• You must respect your teachers – debes respetar a tus profesores

and use should for convenience or less strong advice:

• You shouldn’t eat so many cakes – no deberías comer tantos pasteles.

Although not so frequently used as should, especially in negative sentences, ought to is synonymous with should with the meaning of ‘deber’:

• You ought to give up smoking – deberías dejar de fumar
• You ought to get up earlier – deberías levantarte más temprano

Practice -3

Complete with should or must as required

a.- You’re getting a pot belly; you _________ drink so much beer.

b.- There’s a school nearby, you _________ drive more slowly.

c.- He’s losing too much blood, we ________ call an ambulance at once.

d.- You work too hard, I think you _____________ slow down.

KEY 3

a.- shouldn’t; b.- must; c.- must; d.- should.

4.- MUST IN THE PAST

In indirect speech you can use must or had to, but only had to in direct speech:

• The boss told me that I must /had to get to work earlier - el jefe me dijo que debía/tenía que llegar más temprano al trabajo.
• He had to sell his house - tuvo que vender su casa.

Practice-4

Turn the following sentences into the past

a.- My father always tells me that I must obey the law.

b.- My husband is away, so I must walk the dog.

c.- He must retire at 55 owing to bad health.

d.- The cleaning lady is ill, so I must make the beds.

KEY 4

a.- My father always told me that I must/had to obey the law. b.- My husband was away, so I had to walk the dog. c.- He had to retire at 55 owing to bad health. d.- The cleaning lady was ill, so I had to make the beds.

5.- ABSENCE OF OBLIGATION/PROHIBITION

We all know that mustn’t is used to express prohibition, and needn’t or not have to for absence of obligation:

• You mustn’t do it - debes hacerlo
• You needn’t do it/you don’t have to do it - no tienes por qué hacerlo

But, attention, if there was no need for you to do sth, but you did it nevertheless, needn’t have is used:

• You needn’t have done it – no tenías que haberlo hecho

and if there was sth that you had to do, but you didn’t do it, use should have and notmust have, because must have indicates supposition:

• You should have done it – deberías haberlo hecho

Practice- 5

* Insert needn’t or mustn’t according to whether the sentences express obligation or absence of obligation

a.- You ____________ cut the roses in the park; it’s forbidden.

b.- You ____________ tell him, I’ve already done it.

c.- You ____________ wake me up; I’ve bought an alarm clock.

d.- You ____________ smoke in the office.

e.- Why did you order chicken as well? you __________ have ordered so much food

** Complete now with must have or should have according to whether you want to express supposition or sth that had to be done and wasn’t done

a.- “He didn’t phone me.” “He _____________ forgotten.

b.- “Sorry I dropped the glass”. “You ____________ been more careful.

c.- “A burglar entered my house last week”. “You ____________ left the door open; you _____________ locked it.”

KEY 5

* a.- mustn’t; b.- needn’t; c.- needn’t; d.- mustn’t; e.- needn’t.

** a.- must have; b.- should have; c.- must have; should have.