MODAL VERBS

Unit 6: Grammar section.

THREE BASIC RULES

Invariable verbs: -s No auxiliaries: do / does Always followed by INFINITIVE

ExceptBe able to + INF

Have to + INF

Need to + INF

Present: Can / can’t + INFEx: Jim can draw very well.

Future: Will / won’t + be able to + INFEx: When I finish my project I will be able to

go out with my friends.

ABILITY

ABILITY Past:

Was / wasn’t or were / weren’t able to + INF[Particular past ability: “poder”]Ex: The boat sank near the beach, so we

were able to swim to the shore.

Could / couldn’t + INF[General past ability: “saber”]Ex: We could swim when we were 5.

Necessity / Obligation:

Must + INF [Strong / personal]Ex: You must wear a helmet when you ride a

bike.

Have to + INF [Task]Ex: I have to do my homework before dinner.

Need to + INF [Necessity]Ex: I need to go to the bank.

OBLIGATION

Lack of Obligation:

Don’t / doesn’t have to + INFEx: You don’t have to sweep the floor, there is

someone to do it for you.

Needn’t + INFEx: You needn’t bring anything to the dinner.

OBLIGATION

Need is followed by to + INF in affirmative forms:

Ex. I need to go to the bank.

The negative form, Needn’t , is only followed by the INF:

Ex. You needn’t use your car.

BE CAREFUL!

BUT

Prohibition:

Mustn’t + INFEx: Students mustn’t run in the corridors.

Can’t + INFEx: You can’t use the computer after

midnight.

OBLIGATION

Affirmative:

Should / Ought to + INFEx: You should / ought to stop eating

chocolate if you want to lose weight.

Negative:

Shouldn’t + INFEx: You shouldn’t eat so much chocolate if

you want to lose weight.

ADVICE

Sure:

Must + INF [I am sure that…]Ex: She must be happy because she has

won the car.

Impossible: [It’s impossible that…]

Can’t + INFEx: She can’t be at class because she is

abroad.

CERTAINTY

Possible:

May + INF [Stronger]Ex: It may be quicker to travel by train.

Might + INFEx: We might get lost if we don’t use a map.

CERTAINTY

Possibility can also be expressed using:

Can + INFEx: We can paint the walls later.

Be able to + INFEx: I think they will be able to win this time.

Could + INF [Remote possibility]Ex: We could go on Friday evening.

CERTAINTY

REQUEST Formal:

May + INF [Very formal]Ex: May I use your phone, please?

Could + INFEx: Could you tell me the way to the station?

Would + INFEx: Would you like to help me with the luggage?

Informal:

Can + INFEx: Can you speak more clearly?

SUGGESTION & OFFER Suggestion:

Could + INF [Formal]Ex: You could join our team next week.

Can + INF [Informal]Ex: You can sing that song again!

Offer:

Would+ INFEx: Would you like a cup of tea?

PERFECTMODAL VERBS

Actions in the past. Modal + have + participle

Sure:

Must + HAVE + PARTICIPLE[A certainty or logical conclusion about an event in the past]

Ex: The lights are out. Everyone must have left .

Impossible:

Couldn’t + HAVE + PARTICIPLE[A certainty that something did not happen]Ex: She couldn’t have done a better job.

CERTAINTY

Possible:

May / Might + HAVE + PARTICIPLE[A guess about something that happened in the past. You’re not sure of it]

Ex: She may / might have read this book, but I’m not sure.

CERTAINTY

Only in affirmative:

Could + HAVE + PARTICIPLE[The ability to do something in the past, but which in the end was not done]

Ex: You could have avoided that accident.

ABILITY

CRITICISM OR REGRET In affirmative:

Should / Ought to + HAVE + PARTICIPLE[Advice which was not followed in the past]Ex: You should /ought to have listened to me. [Expectations which were not fulfilled]Ex: They should / ought to have nominated the

film for an Oscar.

In negative:

Shouldn’t + HAVE + PARTICIPLE[Criticism that is given after an event]Ex: He shouldn’t have refused the opportunity.

DESIRE

Would + HAVE + PARTICIPLE[Desire to do something in the past which in fact could not be done]

Ex: I would have lent you my car but my father needed it too.

UNNECESSARY ACTION

Needn’t + HAVE + PARTICIPLE[Something that was done but it was not necessary]

Ex: You needn’t have raised your voice.