Материал: doichik_oia_modal_verbs_theory_and_practice

To express advisability on a scale which

depends on the degree of choice (from

Should I go there alone? (=asking for

advisability to necessity) according to the

advice)

subjective point of view of the speaker we

use the following modal verbs and phrases:

should

(= „it is advisable in my

You should be more attentive

opinion, it is your duty‟)

We should always help each other

ought to (outside duties and

You ought to vote

regulations)

You ought to clean after yourself

had better (stronger than should,

He‟d better see a doctor

particular recommendations

You‟d better not argue now

about the future; has the

I‟d better not find you in my room again

elements of threat, warning

You‟d better not ignore these symptoms

or urgency)

She‟d better stop smoking

am/is/are to (instructions)

You are to report for duty at 7

need (to) (= it is necessary to)

He needs to type it again

have to

(alternative to must in past,

I will have to read it again

future and perfect tenses)

She must lose weight

must

(inescapable obligation and

necessity, esp. in the

speaker‟s opinion)

The negative forms:

You shouldn’t behave like that

shouldn’t, oughtn’t, had better not

You oughtn’t to park there

express inadvisability

You‟d better not lift heavy things

don’t have to / don’t need to / needn’t

I needn’t be there so early (no necessity)

express lack of necessity

He doesn’t have to come until tomorrow

mustn’t expresses strong prohibition

You mustn’t be late

Life belts must not be removed (public

notice)

Speaking about the present situation we

use must to render:

-

personal opinion

You must do your best!

-

obligation

on oneself

(speaker‟s

I must give up smoking

authority)

We really must do something about it!

-

instructions

The electricity must be switched off.

We use have to to express:

- necessity due to external conditions

I have to work on Sundays

-

something

required

by

external

You have to leave at six not to be late

authority

They have to spend the whole week at

must expresses stronger obligation than

home, since it‟s too cold.

have to

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* Note

*

Must can be used to express emphatic

You really must take a holiday this year

advice

You must see this film

** Note

**

In conversation we often use Must you…?

Must you always be late?

Do you have to…? to express a reproach

Do you always have to interrupt me?

meaning „Can‟t you stop?‟

The degree of necessity rises from need

(to) to must:

We must breathe to live

must

(absolutely necessary)

Children have to clean their teeth

have to (necessary)

We need to have three meals a day

need to (necessary, but not inescapable)

*** Note

***

need has some characteristics of a modal

Need you leave now?

verb:

Need I send this message again?

- It doesn‟t take auxiliary verbs in

He need know what to do

questions

I needn’t go there

-

It is

followed by the bare infinitive

You needn’t have come so early

(need+V1 to refer to the present;

-Need you have told him about that?

need+have+V3 to refer to the past)

(the possible answers: -Yes, I had to (=I

-

It is used in the negative form needn’t

had no choice), -No, I needn’t have (=I

to express lack of necessity

had a choice))

- It combines with adverbs hardly, never,

She need never be told this

seldom, rarely, scarcely to make

I need hardly tell you about my feelings

negative statements

and can be used as a regular verb:

I don’t need to take a taxi

-

it takes auxiliaries

Why did you need to go to the doctor?

- it is followed by the to-Infinitive

Will you need to be instructed?

- it is used in all tenses

They needed to leave earlier

To express past (in)advisability we use

You should have come to the office at 9

should(n’t) have + V3 /

(but you didn‟t)

ought(n’t) to have + V3.

He shouldn’t have said so (but he did)

The advisable action wasn‟t carried out.

He ought to have helped us (but he

didn‟t)

To express past necessity we use had to /

I had to leave at 9 (and I did, because it

needed to. The necessary action was

was necessary)

carried out.

I‟ve had to call her several times

already

We had had to wait for an hour before

they checked the information

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