Modal verbs and their meaning
What are modal verbs?
Modals (also called modal verbs, modal auxiliary verbs, modal auxiliaries) are special
verbs which behave irregularly in English. They are different from normal verbs like
"work, play, visit..." They give additional information about the function of the main
verb that follows it. They have a great variety of communicative functions.
Here are some characteristics of modal verbs:



They never change their form. You can't add "s", "ed", "ing"...
They are always followed by an infinitive without "to"
They are used to indicate modality and allow speakers to express
certainty, possibility, willingness, obligation, necessity, ability
List of modal verbs
can, could, may, might, will, would, shall, should, must
The verbs or expressions ought to, had better, and need not behave like modal
auxiliaries to a large extent and may be added to the above list
Use of modal verbs:
Modal verbs are used to express functions such as:
1.
2.
3.
4.
Permission
Ability
Obligation
Prohibition
5.
6.
7.
8.
Lack of obligation
Advice
possibility
probability
Examples of modal verbs
Here is a list of modals with examples:
Modal Verb
must
must not
can
could
may
might
need not
should/ought
to
had better
Expressing
Example
Strong obligation
You must stop when the traffic lights turn red.
logical conclusion / Certainty
He must be very tired. He's been working all day
long.
prohibition
You must not smoke in the hospital.
ability
I can swim.
permission
Can I use your phone please?
possibility
Smoking can cause cancer.
ability in the past
When I was younger I could run fast.
polite permission
Excuse me, could I just say something?
possibility
It could rain tomorrow!
permission
May I use your phone please?
possibility, probability
It may rain tomorrow!
polite permission
Might I suggest an idea?
possibility, probability
I might go on holiday to Australia next year.
lack of necessity/absence of
obligation
I need not buy tomatoes. There are plenty of
tomatoes in the fridge.
50 % obligation
I should / ought to see a doctor. I have a
terrible headache.
advice
You should / ought to revise your lessons
logical conclusion
He should / ought to be very tired. He's been
working all day long.
advice
You 'd better revise your lessons
Remember
Modal verbs are followed by an infinitive without "to", also called the bare infinitive.
Examples:



You must stop when the traffic lights turn red.
You should see a doctor.
There are a lot of tomatoes in the fridge. You need not buy
Modals in the present and past
Generally speaking modals in the past have the following form:

modal + have + past participle
Example:


Present:
You should see a doctor.
Past:
You should have seen a doctor
Except for modals that express obligation, ability and lack of necessity/obligation:



Obligation:
Present = I must / have to work hard. -- Past = I had to work hard.
Ability:
Present = I can run fast. -- Past = I could run fast when I was young.
Lack of necessity:
Present = You don't have to / needn't take your umbrella. -- Past = You didn't have to /
didn't need to take your umbrella.
Modals in the Present
Obligation
You must / have to stop when the traffic lights are
Modals in the Past
You had to stop.
red.
Advice
You should see a doctor.
You should have seen a doctor
Prohibition
You mustn't smoke here.
You mustn't have smoked there.
Ability
I can run fast.
I could run fast. now I am old.
Certainty
He has a Rolls Royce. He must be very rich.
He must have been rich. He had a big
He can't be American. His English is terrible.
house and an expensive car.
He can't have written that poem. He was
illiterate.
Permission
Can I go out?
She could drive her father's car when she
was only 15.
Possibility
It may / can / could / might rain. It's cloudy.
I guess it may / can / could / might have
been Lacy on the phone.
Lack of
You don't have to / needn't buy any tomatoes.
You didn't have to / didn't need to
necessity
There are plenty in the fridge.
buy tomatoes.
What's the difference between must and have to?
Must and have to are modal verbs in English. This page will guide you to the proper use of these
modals.
Must
1. We use must to make a logical deduction based on evidence. It indicates that the speaker is
certain about something:
Examples:


It has rained all day, it must be very wet outside.
The weather is fantastic in California. It must be a lot fun to live there.
2. Must is also used to express a strong obligation.
Examples:


Students must arrive in class on time.
I must go to bed.
Have to
Like must, have to is used to express strong obligation, but when we use have to there is usually
a sense of external obligation. Some external circumstance makes the obligation necessary.
Examples:


I have to send an urgent email.
I have to take this book back to the library.
REMEMBER: when we cannot use CAN, we use BE ABLE TO; when
we cannot use MUST, we use HAVE TO
Practice on Modals
1. Modal verbs have various functions, some essential ones of which are listed
below. Reading the sample sentences, classify the underlined modals according to
their functions:








possibility:
certainty:
deduction:
obligation:
permission:
necessity:
lack of obligation:
advice:







expectation:
preference:
requests:
offers & invitations:
habitual past actions:
ability:
typical behaviour:
1. You should bring some warm clothing. It may snow while we're up there.
2. You had better not turn down his proposal.
3. Harry would do a thing like that! I've known him for years.
4. He would sometimes get out of control, don't you remember?
5. Ben has studied enough, so he should pass the advanced driving test tomorrow.
6. Could you tell me the time?
7. I would rather lick an ashtray than kiss a smoker.
8. You mustn't forget to post the letters or the boss will surely go crazy.
9. I needn't get the drinks ready because we might not have the party tomorrow.
10. No one but Tom was able to swim across the lake.
11. What's that noise? Could it be a cat on the roof?
12. At one time people used to walk long distances on foot but now we need to take a taxi or something
when we have to travel even the shortest distances.
13. My brother could play the violin with expert skill when he was a child.
14. Will you please try not to raise your voice? The baby is asleep.
15. She must be out of the town at the moment. No one has seen her nowadays.
16. Would you like to spend the night in my flat?
17. You must watch every step of yours while crossing a mine field.
18. We don't need to be told what's to be done.
2. Put in ‘can’ / ‘can’t’ / ‘could’ / ‘couldn’t’. If none is possible, use ‘be able to’ in the
correct tense:
1. _________________ you swim when you were 10?
2. We _________________ get to the meeting on time yesterday because the
train was delayed by one hour.
3. He _________________ arrive at the party on time, even after missing the
train, so he was very pleased.
4. He’s amazing, he _________________ speak 5 languages including Chinese.
5. I _________________ drive a car until I was 34, then I moved to the
countryside so I had to learn.
6. I looked everywhere for my glasses but I _________________ find them
anywhere.
7. I searched for your house for ages, luckily I _________________ find it in the
end.
8. She’s 7 years old but she _________________ read yet – her parents are
getting her extra lessons.
9. I read the book three times but I _________________ understand it.
10. James _________________ speak Japanese when he lived in Japan, but he’s forgotten most of it
now.
3. Put in “mustn’t” or ‘don’t / doesn’t have to’:
1. We have a lot of work tomorrow. You _______________ be late.
2. You _______________ tell anyone what I just told you. It’s a secret.
3. The museum is free. You _______________ pay to get in.
4. Children _______________ tell lies. It’s very naughty.
5. John’s a millionaire. He _______________ go to work.
6. I _______________ do my washing, because my mother does it for me.
7. We _______________ rush. We’ve got plenty of time.
8. You _______________ smoke inside the school.
9. You can borrow my new dress but you _______________ get it dirty.
10. We _______________ miss the train, it’s the last one tonight.
4. Put in ‘must + infinitive’ or ‘must + have + past participle’:
1. Keiko always does really well on exams. She _____________ (study) a lot.
2. That woman drives a very expensive car. She _____________ (have) a lot of
money.
3. You _____________ (practise) a lot before you gave your speech. It was
really great.
4. When Lizzie got home yesterday, there were flowers on the table. Her
husband _____________ (buy) them.
5. Where is my purse? I saw it earlier, so it _____________ (be) in this room.
6. Sarah couldn’t find her glasses. She thought she _____________ (leave) them
at her office.
7. It _____________ (be) cold outside. That man in the street is wearing a coat.
8. All my plants _____________ (be) dead! I forgot to water them before I left
for my holiday.
9. Susie is so late! She _____________ (miss) the train.
10. There’s rubbish all over my garden! A fox _____________ (be) in the bin.
5. Put in ‘can’t’ or ‘must’:
1. Why is that man looking around like that? He _____________ be lost.
2. That woman _____________ be a doctor! She looks far too young.
3. John always fails the tests, even though he’s clever. He _____________ study
enough.
4. The food is really good at that restaurant. They _____________ have a great
chef.
5. Who’s that at the door? It _____________ be Susie – she’ll still be at work
now.
6. This _____________ be John’s house. This house has a red door, and it’s
number 24, just like he said.
7. Julie _____________ have much money, or she would buy a new car. Her old
one is falling apart.
8. He _____________ be at work now, can he? It’s nearly midnight.
9. What a lot of lovely flowers you have! You _____________ really like
gardening.
10. David _____________ drink a lot of coffee. He’s finished two packets already
this week!
6. Re-write the sentences so that they have the same meaning as the original. You
must use a modal verb:
1. I'm sure John locked the office before leaving. He always does
2. If I were you I would tell him the truth.
3. It isn't necessary for her to phone me back
4. Ann finished the project on her own although it wasn't necessary to do so.
5. It was a mistake to sell the house. I wish I hadn't.
6. Perhaps we'll go swimming tomorrow
7. I think Mary is probably at home because the windows are open.
8. Perhaps John knew about the trip, but I'm not sure.
9. Perhaps she was at work when the earthquake struck.
10. It's absolutely necessary that we finish the article today.
11. It wasn't necessary for him to behave like that.
12. It's quite possible that they went away last weekend
13. I'm sure Ann didn't send that letter.
14. It was a mistake not to accept his offer. I wish I had.
15. It is essential that we talk before the meeting starts.
16. I don't think Ann robbed the money. It's impossible.
17. Why don't we go on a camping trip?