So tell me,

what type of words are these?

They're modal verbs.

Now, I've been getting lots of questions

about modal verbs from you lately

so, I'm going to share some useful tips

to help you use them a little more

effectively when you're speaking English.

Now, these modal verbs are auxiliary verbs,

just like be, do and have

because they work together with a main verb.

You always have a modal verb with a main verb

and the main verb that follows is always

in the bare infinitive form - without to.

I could go..

You should take...

They would like...

Paul may borrow...

Now, these modal verbs are used in English

to express something.

They have a purpose!

So, we need to try and understand that purpose today.

Now, they can be used to talk about

possibility and probability.

To talk about how likely something is.

Now, remember you're always using that modal verb

with a main verb.

So, how likely is it that that action will happen?

Are you certain?

You're sure. You're confident that will happen.

Is it probable?

Is it likely to happen?

Is there a good chance it will happen?

Is it possible?

Or is it unlikely?

Now, in all of these situations

you can use a modal verb to explain how certain you are

that something will happen,

how possible something is.

Now, these same modal verbs can also be used

to explain 'ability'.

So, how able you are to do something.

They can be used to ask permission, make requests

and offer help.

In fact there's quite a few different uses

so I'm going to split this lesson in two.

And I'm doing this because I want to take this slowly.

I don't want you to feel overwhelmed and confused,

so let's just take one step at a time.

In this lesson,

I'll talk about how we use modal verbs to talk about

certainty, probability and possibility.

So, this is how likely something is to happen.

Or, if it's possible at all!

And the next lesson

will focus on ability and the other uses.

So, try not to worry about them right now.

But, make sure that if you're not a subscriber

you click that red button and subscribe so that

you find out when that next lesson is available.

Okay so let's start with probability,

how likely something is to happen.

Now, we use 'will' to talk about the future,

when we're confident that something will happen.

We believe it. We're certain it's true.

The sun will rise tomorrow.

(I'm) pretty sure that will happen.

Ashley will be late.

Well... She's always late

so I definitely believe that to be true!

If you don't take a jumper, you will get cold.

It's freezing out there!

You'll also hear 'will' used

to give reassurance when you want to confirm

that something is true.

You know when your mum tells you

"You will pass the exam. Don't worry!"

even though you're really not sure that's true.

She's using 'will' to tell you that she's confident,

she believes in you.

When you're upset,

your friends tell you "It will be okay".

They're confident,

they believe that everything will be okay.

Now if you're certain

that something is not going to happen,

use 'will not' or' 'won't'.

If they walk, they won't arrive in time.

It's too far!

I'm certain that that won't happen.

We also use 'must' when we are confident

and sure of something that is happening in the present.

And usually we have a reason or an explanation

to tell us why something is happening.

The baby's crying. He must be hungry.

I thought Sarah would be here by now.

She must be stuck in traffic.

They didn't eat any of the meat.

They must be vegetarian.

Notice how I've given a reason

for all of these examples to show why I believe

something to be true

and it's quite common when you're using 'must'.

It explains that you are

quite confident about the statement

and you're able to give a reason to explain

why you're so sure.

To use 'must' to talk about the past

when you're quite sure that something happened,

then use 'must have'.

After flying for 36 hours, you must have felt exhausted.

I thought I'd do better in the exam.

I must have been really nervous.

Jack's not here right now. He must have thought

that you were meeting him downstairs.

Now see how this creates the perfect tense.

The main verb following 'have'

is in the past participle form.

So when talking about the present or the future,

'must' is followed by the bare infinitive form

but when talking about the past,

'must' is followed by 'have'

and the past participle verb form.

And this pattern is true for many of the modal verbs

that we'll talk about today.

We use 'should' to say that something is likely.

We're not a hundred percent certain

but we believe it to be true.

They left an hour ago,

they should be here by now.

If they take the car, they should arrive by three.

To talk about the past, we use 'should have'.

It's the same pattern.

I didn't realise he was unwell.

We should have offered to take him to the doctor.

The school knew Sam was going to be late.

They should have called her mother.

Now let's talk possibility.

So if you're making really general statements

about something that is possible,

use 'can'.

People can be really rude.

Be careful because it can be

quite dangerous on the streets at night.

It can be really hard to find a speaking partner

to practise English with.

It can take over twelve hours

to hike through those mountains.

Now these are all general statements,

they're not specific.

I'm saying these statements are possible

but I'm not saying exactly what is happening.

Now, in this context

'could' is used as the past tense of 'can'.

I remember winters in London.

Weeks could go by without ever seeing the sun!

So when we're uncertain or unsure about the present

and the future,

we use the modal verbs 'could'

'might' and 'may'.

They explain that something is possible

but not certain or guaranteed.

If you wait near the door on Lewis Street,

you could see the Prime minister leaving.

They might arrive before lunch.

But I'm not sure.

I may need to borrow your car.

Now 'might' and 'may' here are very similar.

There is a very slight difference between the two

in that 'might' tells us that the outcome

is a little bit less likely.

But the truth is that ninety-nine percent of native English

speakers don't even realise this.

So you don't need to worry about the difference at all.

When used in spoken English, you can use either

when talking about possibility.

Just consider them to be the same.

We may go on a holiday in September.

We might go on holiday in September.

Close enough!

The meaning of this sentence is so similar

but the second one suggests that it's a little less likely

- that's all!

We can also use 'could' to explain that we are

uncertain or unsure about the future.

It could rain this afternoon.

It might rain this afternoon.

It may rain this afternoon.

Now all of these sentences tell us that it's possible

but not certain.

There is a chance that it will happen.

Simon could arrive before us.

Simon might arrive before us.

Simon may arrive before us.

Now these examples

all talk about the present or the future.

And the modal verb is followed

by the bare infinitive verb form.

But now,

we'll go into the past, back in time.

Then we use these same modal verbs with 'have'

followed by the past participle verb

so suddenly we're using the present perfect tense.

They might have finished dinner by now.

I'm worried. Something could have happened to Sara.

Okay so that was talking about possibility.

Now,

let's focus on

impossibility - when something is not possible,

when we know that something is unlikely to happen.

The chances of it happening are

really, really, really small.

When we think that something is impossible,

we use the negative forms of 'can' and 'could'.

You can't be serious!

It's not possible. I don't believe you!

Now this expression is often used after someone

says something that you just don't believe.

When we think that what is said

is very unlikely to be true.

When we told them they'd won,

they couldn't believe it!

He said he was in a band called 'Meatball'!

He couldn't have been serious.

So when spoken, these negative forms

are usually contracted.

Can't.

Couldn't.

And couldn't've.

Now you will never see this last one

written as a double contraction

but you will hear it spoken.

Couldn't've.

You will hear people pronounce

the full negative form though

especially to add emphasis,

to make the meaning stronger.

That cannot be true!

You can make it even more dramatic

by stressing every single word.

That can not be true!

Okay so let's summarise now.

If you are certain about something use 'will'

or use 'won't' if you are certain that something

is impossible.

Now if you're confident about something and you have

a reason for believing that

use 'must' or 'should'.

If you're talking about something generally

that's possible, use 'can'.

If you are not certain but it's possible

use 'might', 'may' or 'could'.

So remember that there are different meanings

for all of these modal verbs

and we're going to talk about these more in the next lesson.

Well I hope that you enjoyed that lesson!

I hope you feel a little more confident

using modal verbs to talk about

possibility and probability.

Now remember that the next lesson will talk about

how these modal verbs can be used

for ability, to ask for permission,