Complete Guide to English Modal Verbs - English Grammar Lesson


Hi, I’m Stephanie.

Welcome to Oxford Online English!

In this lesson, you can learn about English modal verbs.

What are modal verbs?

What do they do?

Why do you need them?

Youll see answers to all these questions in this class.

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Let’s get back to our topic with some basic points you should know to use modal verbs


Shall we start?

Yeah, we probably should!

So, can you tell me something about modal verbs?


What would you like to know?

I must know everything about them!

That might take a long time!

Youll help me, though, right?

Of course, even though it may be challenging.

There are nine modal verbs in English.

You just heard a dialogue with nine lines.

Each line contains one modal verb.

Can you name the nine modal verbs in English?

Maybe you know them already, but if not, you can go back and try to find them in the dialogue.

The nine modal verbs are: can, could, may, might, will, would, shall, should and must.

What do modal verbs do, and how are they different from other verbs?

Also, why are they so important?

Modal verbs add information to other verbs.

That’s their job.

They can add ideas like possibility, uncertainty, or obligation to another verb.

Grammatically, modal verbs follow their own rules.

Let’s see what this means.

Rule number one: a modal verb is followed by an infinitive verb, withoutto’.

For example: ‘She can speak fluent Spanish.’

We shouldn’t do anything until we know more.’

They won’t be here before ten.’

You can’t put a noun after a modal verb, or an -ing verb, or anything else, only an

infinitive verb withoutto’.

Rule number two: modal verbs can’t be used in different times or tenses.

Modal verbs don’t have past, perfect or future tenses like regular verbs do.

There are some cases where this isn’t 100% true.

For example, ‘couldis the past tense ofcanin some cases.

Wouldsometimes acts like a past version ofwill’.

However, ‘couldcan also have a present or future meaning.

It’s better to think about each modal verb individually.

Rule number three: modal verbs are *auxiliary* verbs.

That means you make negatives by addingnotto the end of the verb.

For example: can, can’t.

Would, wouldn’t.

Might, might not.

Negative modal verbs are often contracted, althoughmight notandmay not

are usually written fully, without contractions.

Forwillandshall’, the spelling changes in the negative: will, won’t; shall,


To make a question, move the modal verb before the subject.

For example: ‘Should I tell him?’

What would you do?’

What about the other question: why are modal verbs important?

Modal verbs can express many basic concepts which you will need regularly, in any situation.

Modal verbs are used to express obligation, give advice, talk about possibility and probability,

ask for permission, and more.

Next, let’s look at the meanings which modal verbs can express in more detail.

Can I ask you something?


I’m thinking I might ask for a transfer to the Singapore office.

I’ve always wanted to live abroad, and I think now’s the right time.

What do you think?

I think if youve thought about it, then you should try it.

Better to regret something you did than something you didn’t do; that’s my view.


Will they agree, though?

You don’t know till you ask!

Anyway, I’m sure theyll agree; you have a good track record here, and if you come

back later youll have a lot of valuable experience.

So, they should say yes.

I’m just worried, because I know that Olga asked for a transfer to Canada, and they wouldn’t

let her

That’s a totally different situation.

Olga’s a tax specialist; she’s irreplaceable.

I wanted to ask one more thing: will you write a reference for me?

No problem!

I’d be happy to.

There’s one more thing you must do before you apply.

What’s that?

Talk to the Singapore office.

I can put you in contact if you need.

That’s great!

Thanks so much for helping me out.

You can use modal verbs to express nine fundamental ideas.

Maybe youre thinking: “That’s nice and easy!

There are nine modal verbs, and nine meanings, so each verb must have one meaning, right?”


Unfortunately, it’s more complicated than that.

First, the nine meanings are broad.

Each contains several smaller ideas.

Secondly, every modal verb can have more than one meaning.

Anyway, well worry about that later!

For now, let’s look at the nine fundamental ideas which modal verbs can express.

Asking permission.

Expressing possibility or impossibility, when you think something could be true or not.

Giving advice or suggestions.

Expressing certainty or uncertainty, when youre sure something is true or not.

Expressing probability, when you think one result is more likely than another

Expressing willingness or refusal, for example when someone lets or doesn’t let someone

else do something.

Making a request or an offer.

Expressing an obligation, when it’s necessary to do something.

Expressing ability, when someone has the capacity to do something, or not.

In the dialogue, there’s at least one example of each of these nine basic meanings.

Can you find them?

If you want a challenge, go back and listen to the dialogue again.

Try to find one sentence with a modal verb which expresses each of the nine basic meanings.

Let’s look together.

Here are nine sentences from the dialogue.

The first sentence is asking permission.

You usecanto askIs this OK?’

Sentence two is talking about possibility.

Youre saying that something is possible, but not certain.

The third sentence is giving advice.

Number four is expressing certainty.

Youre sure that something is true now, or that something will happen in the future.

In case youre wondering, possibility and certainty are closely related.

Were separating them, but you could also see them as two sides of the same idea.

However, probability, as in sentence five, is different.

Here’s a question: what’s the difference between probability and possibility?

Probability has different levels.

Something can be 90% probable, or 50% or 20%, or whatever.

Possibility is binary: either something is possible, or it isn’t.

It doesn’t make sense to say that something is 50% possible.

This might sound abstract, but it’s relevant to using modal verbs.

Here, ‘shouldexpresses probability.

The sentenceThey should say yesmeans that it’s more likely theyll sayyes


The sixth sentence expresses refusal.

Wouldn’t’ here has a similar meaning torefused to’.

Number seven is a request, when you ask someone to do something for you.

The eighth sentence expresses an obligation.

Musthere means that it’s necessary to do something.

Finally, the ninth sentence expresses ability.

So, there’s a lot of information here!

What should you take away?

Let’s look at two key points.

First, not every modal verb was used in these nine sentences.

There’s nocould’, noshalland nomay’.

What does this tell you?

It shows you what we told you before: every modal verb can have more than one meaning.

Also, it shows you that every idea, like obligation, certainty, and so on, can be expressed by

more than one modal verb.

Let’s look at this point in more detail.

Can you look at something for me?


What’s up?

It’s my laptop.

It’s acting weirdly.

I know youre good with these things, so

What’s the problem exactly?

It keeps freezing, and I can’t do anything for a while.

Sometimes it’s just a few seconds, but sometimes it goes on for half an hour.

It’s really annoying!

Older laptops can get like that sometimes.

But I only bought it six months ago!

Do you have an antivirus program?

Yes, and I do scans regularly.

It can’t be a virus.

I’m not so good with technology, but I am pretty security conscious.


That’s probably not the problem, then.

Can I take it for an hour or so?

I’ll need your login password, too.

That way I can take a proper look.

OK, here.

Thank you so much!

In this dialogue, there were five different sentences using the modal verbcan’.

Do you remember them?

Here they are.

In each sentence, ‘canhas a different meaning.

Think about the nine basic meanings of modal verbs, which you saw in section two.

Can you explain the meaning ofcanin each of these sentences?

Can you see how theyre different?

Can you look at something for me?’ is a request.

‘I can’t do anything for a whileexpresses ability.

Older laptops can get like that sometimesexpresses a general possibility.

It’s like sayingIt’s common for older laptops to get like that.’

It can’t be a virusexpresses certainty.

It’s like saying ‘I’m sure it isn’t a virus.’

Can I take it for an hour or so?’ is asking permission to do something.

This is just one modal verb.

Canis an extreme example, because most modal verbs don’t have five different meanings.

Actually, ‘canhas a sixth meaningit can be used to make an offer, as inCan

I help you with anything?’

However, every modal verb has at least two different meanings, and most have three or


So, what’s the point here?

Point one: *really* don’t try to understand modal verbs by translating them into your


Of course, this is true generally, but it’s especially important with modal verbs, because

they don’t translate cleanly between languages.

If you think thatcanin English translates to one verb in your language, youll create

problems for yourself.

Point two: to understand a modal verb in a sentence, you need to understand the context.

Again, this is general advice, but again it’s especially important with modal verbs.

The meaning of a modal verb can be completely different in different contexts.

Point three: the different meanings of a modal verb are unconnected.

Look at two sentences withmust’: ‘It must be lateit’s dark outside.’

You must read this article.

It’s so interesting!’

What doesmustmean in these two sentences?

In the first sentence, ‘mustexpresses certainty.

Youre saying ‘I’m sure it’s late, because it’s dark outside.’

In the second sentence, ‘mustexpresses strong advice.

Most English learners will first learnmustto express obligation, in sentences likeEmployees

must keep records of all expenses.’

Often, theyll think aboutmustby translating it into their language.

Then, when they see the wordmust’, they think about the verb in their language.

If you do this, you might think that other meanings ofmustare somehow connected

to the idea of obligation, or whatever you learned first.

But, there’s no connection.

It’s just coincidence that you use the wordmustin these three sentences.

The meaning is completely different in each case.

There’s no connection except that the word is the same.

Now, let’s look at one more thing you should know about modal verbs.

What time are we supposed to be there?

Ten, I think, but I think we ought to aim to arrive at least fifteen minutes before.

So, that means we have to leave here atwhat?


We’d better leave earlier, I think.

There’s a metro strike tomorrow, so the traffic will be terrible.

Are we going to drive, or take a taxi?

I’m not sure well be able to find a taxi, so I think driving is best.

In the dialogue, you heard several examples of semi-modal verbs.

Do you know what these are?

Here are the sentences you heard.

So, what are semi-modal verbs?

Semi-modals have some of the features of modal verbs, but not all.

Most importantly, semi-modal verbs do the same thing as modal verbs.

They add information to other verbs.

They can express many of the same ideas, like obligation or giving advice.

They don’t follow all the grammar rules of regular modal verbs.

For example, ‘have tois a semi-modal, and you can use it in different tenses: it

has a past tense, ‘had to’; you can use it in the present perfect, ‘I have had to…’

and so on.

Often, modals and semi-modals can be used with the same meaning.

Look at two sentences: ‘Itll rain this afternoon.’

It’s going to rain this afternoon.’

Here, you usegoing to’, which is a semi-modal, to express certainty, in the same way that

you can usewill’.

It doesn’t matter which verb you use in this case.

However, in some cases, semi-modal verbs have their own specific meaning.

For example, ‘supposed tois similar toshould’, but not the same.

Look at two sentences: ‘Were supposed to be there at ten.’

We should be there at ten.’

The basic meaning is similar, but not the same.

If you useshould’, youre saying that *you* think this is important.

If you usesupposed to’, you mean that *other people* think that this is important.

Were supposed to be there at ten’, suggests that someone else has told you to

be there at ten, and maybe it’s not so important to you.

Maybe youre thinking at this point: how many semi-modal verbs are there?

Can you give us a list?

Not really, because it’s not entirely clear what makes something a semi-modal verb.

Many textbooks will say thatneedordareare semi-modals, but theyre

rarely used in this way in modern English.

The most common semi-modals are all in the dialogue at the beginning of this section.

If you understand how to use these six semi-modals, you are doing well!

Finally, a question: which modal verb is most difficult for you to understand and use in


Why do you think that is?

Please share your thoughts in the comments!

Thanks for watching!

See you next time!