# Probability

Level: beginner

## Possibility

We use may, might and could to say that something is possible, but not certain:

They may come by car. (= Maybe they will come by car.)
They might be at home. (= Maybe they are at home.)
If we don't hurry, we could be late. (= Maybe we will be late.)

We use can to make general statements about what is possible:

It can be very cold here in winter. (= It is sometimes very cold here in winter.)
You can easily get lost in this town. (= People often get lost in this town.)

Be careful!

We do not use can to talk about specific events:

A: Where's John?
B: I'm not sure. He may/might/could be
(NOT can) in his office.

Notice the difference in meaning between can and may/might/could:

That dog can be dangerous.
(= Sometimes that dog is dangerous. I know.)

That dog may/might/could be dangerous.
(= Perhaps that dog is dangerous. I don't know.)

can and may/might/could

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Level: intermediate

We use may have, might have or could have to make guesses about the past:

I haven't received your letter. It may have got lost in the post.
It's ten o'clock. They might have arrived by now.
Where are they? They could have got lost.

We use could to make general statements about the past:

It could be very cold there in winter. (= It was sometimes very cold there in winter.)
You could easily get lost in that town. (= People often got lost in that town.)

could and could have

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## Impossibility

Level: beginner

We use can't or cannot to say that something is impossible:

That can't be true.
You cannot be serious.

Level: intermediate

We use can't have or couldn't have to say that a past event was impossible:

They know the way here. They can't have got lost!
If Jones was at work until six, he couldn't have done the murder.

## Certainty

Level: beginner

We use must to show we are sure something is true and we have reasons for our belief:

It's getting dark. It must be quite late.
You haven’t eaten all day. You must be hungry.

We use should to suggest something is true and we have reasons for our suggestion:

It's nearly six o'clock. They should arrive soon.

Level: intermediate

We use must have and should have for the past:

They hadn't eaten all day. They must have been hungry.
You look happy. You must have heard the good news.
It's nearly eleven o'clock. They should have arrived by now.

Probability 1

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Probability 2

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Probability 3

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Probability 4

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Probability 5

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Dear Team,
1) Where are they? They could be lost in the town.
2) Where are they? They could have lost in the town.

What is the difference? Thanks you!!!

Hello DaniWeebKage,

The second sentence is not correct.

Lost is a transitive verb, which means it needs an object. You can lose something (lose money, lose your wallet etc) or you can use a passive construction (be/get lost).

Peter

The LearnEnglish Team

Thank You!!!
1)Where is my book? It could be in the cafe.
2)Where is my book? It could have left in the cafe.
Among the Aforementioned two sentences,
The former is used when we are guessing what could happen in the present.
The latter is used when we are guessing past action or sth( maybe affect the present). Is my summary correct? If not, correct me.

Hello again DaniWeebKage,

I'm afraid your second sentence here is also incorrect for the same reason: leave is a transitive verb in this usage so you need an object or a passive construction. The sentences should read as follows:

1)Where is my book? It could be in the cafe.

2)Where is my book? It could have been left in the cafe.

As far as the modal verbs go (which I think is the main focus of your question), your explanations are correct. We use could + verb to speculate about the present and could have + verb3 to speculate about the past. Well done!

Peter

The LearnEnglish Team

Hi Peter M. I see you using 'could in your comments when replying user questions. Is 'could' used to make a suggestion and means be able to?

We can use the definite article in several ways. When you say 'the bus' it could mean a particular bus (Look - the bus is coming!) or it could have a general meaning and refer to the means of transportation (I prefer the bus to the train).

Second, can I say 'it may mean...'/'it may have'...? If so, is there any difference of meaning?

Hello The LearnEnglish Team!
Could you please help me understand better the difference between "can" and "might, may and could" when we are using them to express possibility?

Hello BobMux,

This is a very general question which requires contextualised examples. Perhaps you can provide an example sentence to illustrate what you mean. This will help to clarify your question and also ensure that our explanation is clear for you.

Peter

The LearnEnglish Team

Hello there!
I would like to know the difference in meaning of these two sentences:
It can be dangerous to cycle in the city.
It could/may be dangerous to cycle in the city.

Hello BobMux,

The sentence with 'can' speaks more about cycling in the city in general, i.e. at any time, in any situation, for any person. The sentences with 'could' or 'may' are more often used to speak about a more specific hypothetical time or situation in the future.

For example, let's say a friend of ours was cycling in the city and had an accident. We could say the first sentence as a kind of comment on how dangerous it is to cycle in the city after this specific event. The second sentence wouldn't work well in this situation -- it's more for a time we're thinking of that could happen in the future, for example, if we're thinking about whether we should take our children cycling in the city tomorrow.

I hope this helps you make more sense of it.

All the best,

Kirk

The LearnEnglish Team

Hello Kirk,
It was rather useful your explanation and thanks a lot. But i am still a bit confused. I would be really happy if you were able to help me understand better modal verbs:
In a book it is said that the modal verbs "might", "may" and could are used to express both possibilty and make a guess. This words is given " this rush might/could/may be a symptom of something more serious". So here is it possibility or making a guess?
And how can i distinguesh between possibilty and making a guess?