The modal verbs are can, could, may, might, mustshall, should, will and would.

The modals are used to show that we believe something is certain, probable or possible:

Possibility:

We use the modals could, might and may to show that something is possible in the future, but not certain:

They might come later. (= Perhaps/Maybe they will come later.)
They may come by car. (= Perhaps/Maybe they will come by car.)
If we don’t hurry we could be late. (= Perhaps/Maybe we will be late)

We use could have, might have and may have to show that something was possible now or at some time in the past:

It’s ten o’clock. They might have arrived now.
They could have arrived hours ago.

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

It can be very cold in winter. (= It is sometimes very cold in winter)
You can easily lose your way in the dark. (= People often lose their way in the dark)

We use the modal could as the past tense of can:

It could be very cold in winter. (= Sometimes it was very cold in winter.)
You could lose your way in the dark. (= People often lost their way in the dark)

Impossibility:

We use the negative can’t or cannot to show that something is impossible:

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

We use couldn’t/could not to talk about the past:

We knew it could not be true.
He was obviously joking. He could not be serious.

Probability:

We use the modal must to show we are sure something to be 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 must 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.

We use the modal should to suggest that something is true or will be true in the future, and to show you have reasons for your suggestion:

Ask Miranda. She should know.
It's nearly six o'clock. They should arrive soon.

We use should have to talk about the past:

It's nearly eleven o'clock. They should have arrived by now.

Exercise

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Comments

Hello,
I am Wondering whether one can use sentences like "It could/may/might have not happened"? Or " It could not/may not/might not have happened"? for negation of possibilities in the past, which also are possibilities and not happened?
Thanks in advance

Hello Seyyed,

The negation can be put in either position with no change in the meaning:

She might/may not have seen him.

She might/may have not seen him.

Both these sentences mean it is possible that she did not see him.

 

Note that 'could' is different. Here the position of the negation changes the meaning:

She could not have seen him. [is is impossible that she saw him]

She might/may have not seen him. [it is possible that she did not see him - the same meaning as above]

 

Best wishes,

Peter

The LearnEnglish Team

Sir, I think He must be sleeping, It's for present, But for past, Should I use this-
I thought He must have been sleeping yesterday ?

Hello SonuKumar,

I'd probably just say 'I thought he was sleeping'. 'I thought' already indicates supposition. Or you could just say 'He must have been sleeping', which indicates supposition. The two forms together would mean you are emphasising the act of making a supposition about him sleeping.

All the best,
Kirk
The LearnEnglish Team

what are the usages of 'Must, must be, and must have been' please help me understand with at least one example for each ?

Hi Kirk
Thank you for answering my previous question . Please I have one more query.
I would go to the cinema , if I have the time.
Is the above sentence correct or should I say I would go to the cinema if I had the time.
Many thanks for your help

Hello sumanasc,

We would use 'had' here. Conditional forms are either about likely/possible events or unlikely/impossible events and we do not mix the two in one sentence. Therefore in your sentence we would either use 'will... have' (likely) or 'would... had' (unlikely).

 

Best wishes,

Peter

The LearnEnglish Team

Hi Kirk
Can you please tell me whether the sentence under modal verb " I could help you , if I find my car " is correct .
Many thanks

Hello sumanasc,

You could probably hear some people say 'I could help you if I find my car', or perhaps find it in writing, but the grammar is a little bit non-standard. This is because the sentence has one verb ('find') in a first conditional structure and the other verb ('could') in a second conditional structure. Please take a look at our Conditionals 1 page to see what I mean.

The sentence in full first conditional structure would be 'I can help you if I find my car' and in full second conditional structure would be 'I could help you if I found my car'.

All the best,
Kirk
The LearnEnglish Team

Hi there,
I have always tried to learn Modals but I find them really difficult!
We use could have to talk about possibility and about ability.
They could have arrived hours ago( did they arrived or not?)
They could have killed him.( did they kill him or not?)
you said we use could have to talk about something was possible at some time but didn't happen. How can we know if this happened or maybe happened?
thanks to the all team members

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