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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

Language level

Intermediate: B1


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

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.

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

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

Hello Rsb

1. The first sentence talks about a past possibility, not a future one. Even if it was in the future from the perspective of the past, from the perspective of now, it is in the past. This sentence is correct, as are the other two that you've labeled as past possibility.

2. No, 'could have' is not used to speak about past ability. Please follow the link and you'll see an explanation of what it can mean.

All the best


The LearnEnglish Team

It's really interesting.

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

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.