MODAL AUXILIARY VERBS

The Modal auxiliary verbs

WILL, SHALL, MAY, MIGHT, CAN, COULD, MUST, OUGHT TO, SHOULD, WOULD, USED TO, NEED

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WILL and SHALL

WILL and SHALL + the infinitive of the verb (shall is rarely used in modern English) are used to form the future:

She will go to London next year.
They will visit us next August.

Sometimes SHALL can indicate obligation or a promise. In this case 'shall' is usually stressed in the pronunciation of the sentence.

He shall go to school! (obligation)
I shall ask him ! (promise)

WILL + infinitive = future :

Examples:

a. Simon will leave for Poland tonight.
b. His next trip will be to Australia.
c. Lucy will change her job at Easter.
d. My parents will celebrate their fortieth wedding anniversary next week.

MAY and MIGHT

1. MAY expresses :

a. Permission
b. Possibility

2. MIGHT expresses :

a. Possibility

MIGHT can replace MAY only when MAY is used to express possibility :
It may rain today.
It might rain today

MAY and MIGHT used to express possibility never take the negative form.

Affirmative form:

She may go to the cinema.
They might go to the cinema.

Negative form:

She may not go to the cinema.
They might not go to the cinema.

Interrogative form:(N.B. Permission only)

May I go to the cinema?
May I leave now?

MAY for PERMISSION

Examples:

a. May I watch television tonight ? Yes, you may.
b. May I leave work at 16.00hrs ? No, you may not.

Note : Here 'may' has the same function as 'can':
Can I help you?
May I help you?

B.MAY and MIGHT for POSSIBILITY

Examples :

a. We may go to dinner tonight, I'm not sure.
or
b. We might go to dinner tonight, I'm not sure.

c. It may snow tomorrow.
or
d. It might snow tomorrow.

e. He may not go to Spain this year.
or
f. He might not go to Spain this year.

CAN and COULD

CAN and COULD are used to express :

-CAPACITY / CAPABILITY

-PERMISSION

-POSSIBILITY.

1. CAN

Note: CAN and COULD cannot be used in the future. The future is formed with 'will be able to'.

CAN

Present
She can speak English.
They can swim.

Past
She could speak English.
They could swim.

Future
She will be able to speak English.
They will be able to swim .

FORM :

Affirmative
Present: can (is able to)
Past: could (was able to)
Future: will be able to
Negative
cannot (isn't able to)
could not (wasn't able to)
will not be able to

Affirmative:
CAN + infinitive:
I can speak French.

Negative:
CAN + not + infinitive
They can not (can't, cannot) play tennis.

Interrogative:
CAN or CAN NOT + subject + infinitive <br> Can't she dance?
Can we come?

Examples:

a. CAPACITY

i. Howard can play the guitar.
ii. Can Jennifer sing?
iii.He can't understand German.

b.PERMISSION

i. Can I park my car here?
ii. No, you can't. It is a no parking zone.
iii.Can I go to the theatre with Michael?

c.POSSIBILITY

i. A car can be a useful means of transport or a dangerous weapon.
ii. She can be very hard to understand sometimes.
iii.We can live life with a positive or a negative attitude.

2.COULD

COULD is also the conditional of CAN and is often used in polite forms.
Could you help me ?

A. For polite requests

Examples:

In the conditional form

a.Could you tell me the time, please?
b.Could you help me, please?
c.Could I have a coffee, please ?
d.Could we come and visit you this evening?

As the past of CAN

e. She couldn't come to dinner last night.
f. They could walk faster when they were younger.
g. Pierre could play the piano when he was a boy.

MUST

MUST = TO HAVE TO: To express obligation or necessity

a. We only use 'must' in the present. For all other tenses we use 'have to'.

b.MUST is used with the infinitive of the verb.
She must leave immediately.

1.Present

2.Past

3.Future

Affirmative
1. I must go
2. I had to go.
3. I will have to go.

Negative
1. I mustn't go.
2. I didn't have to go.
3. I won't have to go.

Interrogative
1. Must I go?
2. Do I have to go?
3. Will I have to go?

Examples :

Present tense:

a.I must see her tonight.
b.She must pass her exams.
c.They must leave before 2 p.m.

Simple Past with 'have to':

d.I had to see her last night.
e.She had to pass her exams.
f.They had to leave before 2 p.m.

Future with 'will have to':

g.I will have to see her tomorrow.
h.She will have to pass her exams.
i.They will have to leave before 2 p.m.

SHOULD and OUGHT TO

a. They are invariable.

b. They have three main uses :

1. Moral obligation

Examples:

You ought to thank them.
They should be happy.
A good mother ought to love her children.

2.Advice

Examples:

You should not (shouldn't) eat too much.
You ought to exercise every day.
He shouldn't drive his car too fast.

3.Probability

Examples:

It should be sunny on the weekend.
They should arrive before dinner.
He is tired. He should sleep well tonight.

FORM:

Affirmative

Subject + SHOULD/ OUGHT TO + infinitive of verb

You should/ought to see the doctor.
Negative

Subject + SHOULD NOT / OUGHT NOT TO + infinitive of verb

You shouldn't / ought not to see the doctor.
Interrogative* :

* OUGHT TO is only used in the interrogative negative form.

SHOULD + subject + verb in the infinitive

Should I see the doctor?
Oughtn't she (to) see the doctor?