Modals – deductions about the present

Do you know how to use modal verbs to say how certain you are about a possibility?

Look at these examples to see how must, might, may, could and can't can be used.

That must be the main entrance. I can see people queuing to get in.
I've lost my keys. They might be at work or they could be in the car.
You can't be bored already! You've only been here five minutes. 

Try this exercise to test your grammar.

Grammar test 1

Modals – deduction (present): Grammar test 1

Read the explanation to learn more.

Grammar explanation

We can use modal verbs for deduction – guessing if something is true using the available information. The modal verb we choose shows how certain we are about the possibility. This page focuses on making deductions about the present or future. 


We use must when we feel sure that something is true or it's the only realistic possibility.

This must be her house. I can see her car in the garage.
He must live near here because he always walks to work.
Come inside and get warm. You must be freezing out there!

might, may, could

We use might, may or could to say that we think something is possible but we're not sure. 

She's not here yet. She might be stuck in traffic.
He's not answering. He could be in class.
We regret to inform you that some services may be delayed due to the bad weather.

They all have the same meaning, but may is more formal than might and could.


We use can't when we feel sure that something is not possible.

It can't be far now. We've been driving for hours.
She can't know about the complaint. She's promoted him to team leader.
It can't be easy for him, looking after three kids on his own.

Note that these verbs, like all modal verbs, are followed by an infinitive without to.

Do this exercise to test your grammar again.

Grammar test 2

Modals – deduction (present): Grammar test 2

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Language level

Submitted by Oliver Goldwyn on Thu, 25/02/2021 - 08:57

If a sentence says "I missed the school bus. I must or might be late for school?"

Hello Oliver Goldwyn,

In this context you are speculating about the future so the correct choice is might.



The LearnEnglish Team

Submitted by WALTHER on Thu, 14/01/2021 - 01:08

Today I learned the big difference between modal verbs that useful daily, I love with learning English every time... thanks for your support...

Submitted by BobMux on Thu, 31/12/2020 - 12:05

Hello The LearnEnglish Team, Would you please explain me difference between two sentences below? 1.Do not call them now. They must be sleeping. 2.Do not call them now. They can be sleeping now.

Hello BobMux,

To be honest, neither of these sound natural to me, but if I were to use one of them, I'd use 1. If I don't know whether they are sleeping or not, but think that they probably are, I'd say 'Don't call them now. They're probably sleeping' (or perhaps 'They might be sleeping').

I'd use 'they must be sleeping' if, for example, I called them but they didn't answer the phone.

I can't think of a situation when I'd use 'can' here.

All the best,


The LearnEnglish Team

Submitted by Yigido on Sat, 12/12/2020 - 06:40

Hi team, I am confused about this sentence:''Snacks can taste be sweet or salty''Why we use -be-? ''Snacks can taste sweet or salty.''Isn't true?

Submitted by Peter M. on Sat, 12/12/2020 - 08:18

In reply to by Yigido


Hi Yigido,

That sentence is not correct. As you say, we do not use 'be' here. You could say either of these:

Snacks can taste sweet or salty.

Snacks can be sweet or salty.

I'm not sure, but I think 'savoury' may be a better word here than salty. It would depend on the context, of course.



The LearnEnglish Team

Submitted by Basheer Ahmed on Thu, 30/07/2020 - 14:12

Hello sir, I found a confusing structure from a book "Practical English Usage by Michael Swan" for Modal verb 'MUST'; I am afraid we must be going. Can you help me clarify the progressive structure with the modal 'MUST', what is the purpose behind using the structure like that? Thank you.

Hello Basheer Ahmed,

Modal verbs have several different uses and meanings. 'must' can be used to express not only deductions, but also obligations, that is, things we need to do.

As Swan explains in his section on different verb forms that can be used to express distancing (and thus make sentences more polite), continuous forms sound more temporary or developing, and so are more polite.

So this sentence is a more polite way of saying 'We must go'.

Hope this helps you make sense of it.

All the best,


The LearnEnglish Team

Hello Sir Kirk, Thank you very much. It is really helpful and helped me in understanding the complete purpose of the usage. Sir, from that topic I have one more question; what does it mean by "DISTANCING" that Michael Swan has put it down many times at different places in his book? Could you please make it clear with examples? Thank you.

Hello Basheer Ahmed,

If you have Swan's book, he explains this in his sections on politeness, but basically, this refers to different verb forms that we can use to put space between us and what we are talking about.

For example, instead of saying 'I need to go', I can say 'I need to be going' -- the continuous form instead of the bare infinitive suggests a temporary need, which can make my need to go sound like something imposed on me rather than my choice. Since it's not my choice, it's more 'distant' from me. In many other languages, this would probably sound ridiculous, but this is one important way in which English verb forms can be used to be more polite.

I hope this helps you make sense of it.

All the best,


The LearnEnglish Team

Submitted by Karan Narang on Fri, 10/07/2020 - 04:27

I could be there just minutes for having my breakfast even though I have a some work after working I may be there to having breakfast.

Submitted by Rsb on Tue, 05/05/2020 - 10:55

Sir, "Could have+ verb 3rd form" is also used for past possibility Guess about something in the past?? Example, Sachin could have played.

Submitted by Kirk on Tue, 05/05/2020 - 16:19

In reply to by Rsb


Hello Rsb

Yes, 'could have' + past participle can be used to speak about a past possibility (see the Intermediate level under Possibility and impossibility). 

All the best


The LearnEnglish Team

Submitted by OlaIELTS on Sun, 03/05/2020 - 15:03

It's really interesting.

Submitted by juniar on Tue, 21/04/2020 - 05:22

How to distinguish between if I don't know they are different meaning: He must be here at 6pm (expectation) He must be here at 6 pm (speculation) Thank you

Hello juniar,

I think the difference between expectation and speculation is merely the speaker's certainty. Expectation suggests that the speaker thinks something is likely; speculation less. Since must already suggests a high degress of confidence I think expectation or strong belief is a better description.

Note that your sentences do not use must in this way. We use must to speculate about the present, not the future. Your sentences describe a future situation. You could say something like this:

It's 6pm. He must be here.



The LearnEnglish Team

Submitted by caroluska on Tue, 07/04/2020 - 23:04

Dear teacher: I´ve recently read a text where I can´t understand the use of may explained on your grammar explanations. Here are the sentences: "You may strike a ball on the ground, or in the air." "You may pick up the ball with your hurley". "You may bounce the ball on the hurley". I really can´t assign this ussage to possibility, permission, etc. Is in the sentences above any other uncommon use of may? And if, which one? It seems to me like the instructions of how hurley is to be played. Thank you very much for your help.

Hello caroluska,

We often use may when describing what is acceptable or allowed within rules, particularly the rules of a game or sport. It's a form of permission: you are allowed to do this by the rules.

You can read more about this on these pages:



The LearnEnglish Team

Submitted by Evgeny N on Mon, 03/02/2020 - 09:42

Dear teachers! In Grammar test 1 we have the next sentence: Come and sit down. You must be tired after the journey Could you tell me please is it possible to use might instead of must? I understood that must, in this case, it's opinion of this person offering to sit down. But isn't it sound a slightly rude and could we use might to make it sound more polite?

Hello Evgeny N,

Grammatically, might is posssible. However, it does not fit the context.

In this sentence must is not a command or an instruction. It is a deduction. It means that the speaker has good reason to believe something and is often used to mean 'I can see that...'.

For example, if someone arrives at my house and I can see that they are wet then I might say 'It must be raining'. I could draw other conclusions, too, such as 'You must be cold'.


We use might in a similar way when we are speculating and are not sure if we are correct. For example, if I try to phone my friend and there is no answer then I could say 'His phone might be turned off' or 'He might be in a meeting'.



The LearnEnglish Team