Modals

Can, could, may, might, must, should, ought to and had better: ability, permission, obligation, prohibition, advice and degrees of certainty.

يتكوّن الدرس من 7 أجزاء: How Modals Work، Ability, Permission and Possibility، Obligation, Prohibition and Advice، Certainty, Probability and Deduction، Hypotheses, Certainty and Doubt، The Imperative: Instructions, Rules and Warnings، Practice and Review.

How Modals Work

1. The family

*can, could, may, might, must, shall, should, will, would, ought to, had better.*

They are not ordinary verbs. They add a judgement to the action: is it possible, necessary, advisable, certain?

2. Four rules that never change

**No "s" in the third person.**

*He can swim*, not *he cans swim*.

**The verb that follows has no "to".**

*You must go*, not *you must to go*. The two exceptions are ought to and have to, which keep it.

**No auxiliary in the negative or the question.**

*You must not go.* · *Can you swim?* Never *do you can*, never *he doesn't can*.

**No infinitive and no -ing form.**

You cannot write *to can* or *musting*; you replace the modal by an equivalent: *to be able to*, *to have to*.

3. The equivalents

Because modals have no infinitive, English borrows other structures for the tenses they cannot form.

> *He can drive.* → *He could drive when he was eighteen.* → *He will be able to drive next year.*

4. The negative forms

5. Modals in the passive

The structure is modal + be + past participle.

Traffic regulations **must be obeyed** by drivers.
This problem **can be solved**.
The letter **should be sent** today.

6. Practice

A. Correct the mistakes.

He cans speak three languages.
You must to respect the rules.
Does she can come with us?
They will can help you tomorrow.

B. Put into the past.

I can swim very well.
Students must wear a uniform.
Visitors may enter the laboratory.

C. Put into the passive.

Drivers must obey traffic regulations.
Somebody should clean this room.

Ability, Permission and Possibility

1. Ability

The difference in the past matters. Could describes a general capacity; was able to describes a single action that actually succeeded.

> *He could swim well, and that day he was able to cross the river.*

2. Permission

*Can* is the everyday form; *may* belongs to formal or written English. In an exam letter, *may* is the safer choice.

3. Possibility

Note the difference between *can* and *may*:

*Accidents **can** happen* = it is possible in general;
*An accident **may** happen tomorrow* = there is a real chance in this case.

4. Requests and offers

**Can / Could you** open the window, please? *(request)*
**Would you mind opening** the window? *(more polite; note the gerund)*
**Shall I** help you? *(offer)*
**Would you like** me to help you? *(offer)*

5. Practice

A. Choose the right modal.

When I was a child, I ______ climb any tree.
After two hours of work, the mechanic ______ repair the engine.
______ I borrow your dictionary, please?
Pesticides ______ be dangerous for health.

B. Complete with *could* or *was / were able to*.

She ______ play the piano when she was six.
Although the road was blocked, they ______ arrive on time.

C. Rewrite more politely.

Open the door.
Give me your pen.

Obligation, Prohibition and Advice

1. Obligation

*Must* is personal: the speaker decides. *Have to* is impersonal: the law, the timetable or the parents decide.

In the past there is only one form: *had to*.

> *Ancient people had to work hard to live.*

2. Prohibition

You **mustn't** smoke in the laboratory.
You **are not allowed to** park here.
Pupils **mustn't** use their phones in class.

3. Absence of obligation

You **don't have to** come if you are tired. *(it is optional)*
You **needn't** bring your book. *(it is not necessary)*
You **don't need to** worry; the exam is easy.

4. The trap: mustn't against don't have to

This is the most frequently tested contrast of the whole chapter.

> *You mustn't copy in the exam.* *(forbidden)* > *You don't have to answer every question.* *(optional)*

5. Advice

Negatives: *You shouldn't cheat.* · *You ought not to cheat.* · *You had better not be late.*

Note that *had better* is followed by the stem without to, and that its negative places *not* after *better*.

6. Regret about a past obligation

I **should have** revised more. *(I did not, and I regret it)*
You **shouldn't have** told him. *(you told him, and it was a mistake)*
He **needn't have** worried. *(he worried, but there was no reason)*

7. Practice

A. Choose *mustn't* or *don't have to*.

You ______ touch this wire; it is dangerous.
Tomorrow is Friday, so we ______ get up early.
Drivers ______ exceed the speed limit.
The entrance is free; you ______ pay.

B. Give advice in three different ways.

> *Your friend eats too much junk food.*

C. Put into the past.

I must finish this report today.
Students must not use calculators.

Certainty, Probability and Deduction

1. The scale

Modals let you say how sure you are, from complete certainty down to a remote chance.

2. Deduction: must against can't

When you reason from evidence, English uses must for a positive conclusion and can't for a negative one. Never *mustn't*, which means prohibition.

3. Deduction about the past

The structure is modal + have + past participle.

He **must have forgotten** the meeting. *(I am sure he forgot)*
She **can't have seen** us; she did not wave. *(I am sure she did not)*
They **may have missed** the train. *(perhaps)*
He **might have taken** the wrong road. *(perhaps, less likely)*

4. The whole set in one place

> *You could have told me!* — it was possible, and you did not.

5. Practice

A. Complete with *must*, *can't*, *may* or *might*.

She has been studying for ten hours; she ______ be tired.
He ______ be the manager; he is far too young.
Take an umbrella: it ______ rain later.
The lights are on, so somebody ______ be inside.

B. Make a deduction about the past.

The ground is wet. → It ______ (rain) during the night.
He did not answer the phone. → He ______ (be) asleep.
She looks surprised. → She ______ (not expect) us.

C. Explain the difference.

He must be working. / He must have been working.
You mustn't be tired. / You can't be tired.

Hypotheses, Certainty and Doubt

1. Making hypotheses about the future

When we imagine how consumption, advertising or technology will change, we are not sure of the future. English expresses these hypotheses with may, might and could + stem.

In a few years, cash **may disappear** from our shops.
Online shopping **might replace** many small shops.
Drones **could deliver** our parcels.

Three points of form:

add **well** to make the hypothesis stronger: *Prices **may well** rise next year.*
use the continuous for an action in progress: *Consumers **may be changing** their habits.*
use the passive when the subject receives the action: *Paper tickets **might be replaced** by phone applications.*

Do not use can for one particular future event: *It can rain tomorrow* is wrong; write *It may / could rain tomorrow*. *Can* states a general possibility: *Advertising can influence children.*

2. The negative: perhaps not, or impossible?

3. Expressions of certainty

4. Expressions of probability

Note the position of *probably*: after *will*, but before *won't*.

5. Expressions of doubt

Careful with spelling: maybe (one word) is an adverb meaning *perhaps*; may be (two words) is the modal + *be*: *Maybe it is true* = *It may be true*.

6. The mistakes to avoid

7. Practice

A. Rewrite with the word in brackets.

Perhaps cash will disappear. *(may)*
I am sure the product is safe. *(no doubt)*
It is probable that prices will rise. *(likely to)*

B. Write three hypotheses about shopping in 2040, using *may*, *might* and *could*.

The Imperative: Instructions, Rules and Warnings

1. The form

The imperative is the simplest form of the verb: the stem, with no subject and no *to*.

2. What we use it for

The imperative is the language of prescriptive texts: user guides, safety notices, recipes, and the set of rules you may be asked to write in the consumer unit.

3. Writing a set of rules

A good list of rules is short, clear and parallel: every line begins with an imperative.

> Safety rules in the school laboratory > 1. Wear safety glasses at all times. > 2. Read the label of every product before using it. > 3. Do not eat or drink in the laboratory. > 4. Never leave a burner unattended. > 5. Report any accident to your teacher immediately.

You can also combine the imperative with a condition: *If the packaging is damaged, return the product.* · *Unless you are sure of the seller, don't pay in advance.*

4. Imperative or modal?

The imperative gives the order directly; a modal states it as a rule.

To sound polite, add please, or turn the order into a question: *Please close the door.* · *Could you close the door?*

5. The mistakes to avoid

6. Practice

A. Turn these sentences into imperatives.

You must keep this medicine in a cool place.
You mustn't use the phone while driving.
I suggest that we compare the prices.

B. Write five rules for safe online shopping, each beginning with an imperative.

Practice and Review

1. The whole chapter in one table

2. Mistakes to avoid

3. Mixed exercise

A. Fill in with the right modal.

Pupils ______ respect their teachers. *(obligation)*
You ______ drink that water; it is not clean. *(prohibition)*
You ______ hurry, we still have an hour. *(no obligation)*
He ______ swim across the river when he was young. *(past ability)*
This medicine ______ cause drowsiness. *(possibility)*
You ______ see a doctor as soon as possible. *(strong advice)*

B. Rewrite with the structure in brackets.

It is forbidden to park here. *(mustn't)*
It is not necessary to bring your book. *(don't have to)*
I am sure he is the new teacher. *(must)*
I am sure she did not receive the message. *(can't have)*
It was a mistake to shout at him. *(shouldn't have)*

C. Put into the past.

I must leave early.
We can meet at six.
Visitors may take photographs.

4. Answers to check yourself

A. 1. must — 2. mustn't — 3. don't have to — 4. could — 5. may / can — 6. had better / should.

B. 1. You mustn't park here. — 2. You don't have to bring your book. — 3. He must be the new teacher. — 4. She can't have received the message. — 5. I shouldn't have shouted at him.

C. 1. I had to leave early. — 2. We were able to meet at six. — 3. Visitors were allowed to take photographs.

الجزء الأول من الدرس مفتوح للجميع، وبقيته مع الاشتراك.

Modals

How Modals Work

How Modals Work

1. The family

2. Four rules that never change

3. The equivalents

4. The negative forms

5. Modals in the passive

6. Practice

Ability, Permission and Possibility

Ability, Permission and Possibility

1. Ability

2. Permission

3. Possibility

4. Requests and offers

5. Practice

Obligation, Prohibition and Advice

Obligation, Prohibition and Advice

1. Obligation

2. Prohibition

3. Absence of obligation

4. The trap: *mustn't* against *don't have to*

5. Advice

6. Regret about a past obligation

7. Practice

Certainty, Probability and Deduction

Certainty, Probability and Deduction

1. The scale

2. Deduction: *must* against *can't*

3. Deduction about the past

4. The whole set in one place

5. Practice

Hypotheses, Certainty and Doubt

1. Making hypotheses about the future

2. The negative: perhaps not, or impossible?

3. Expressions of certainty

4. Expressions of probability

5. Expressions of doubt

6. The mistakes to avoid

7. Practice

The Imperative: Instructions, Rules and Warnings

1. The form

2. What we use it for

3. Writing a set of rules

4. Imperative or modal?

5. The mistakes to avoid

6. Practice

Practice and Review

Practice and Review

1. The whole chapter in one table

2. Mistakes to avoid

3. Mixed exercise

4. Answers to check yourself

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4. The trap: mustn't against don't have to

2. Deduction: must against can't