Questions and negatives:

We make questions by putting the subject after may/might:
May I …? Could I … Might I …? Etc.

The negative forms are may not and might not..

We use may:

  • when we are not sure about something:

Jack may be coming to see us tomorrow.
Oh dear! It’s half past ten. We may be late for the meeting.
There may not be very many people there.

  • to make polite requests:

May I borrow the car tomorrow?
May we come a bit later?

When we use may not for a refusal it is emphatic:

You may not!
You may not borrow the car until you can be more careful with it.

We use might:

• when we are not sure about something:

I might see you tomorrow.
It looks nice, but it might be very expensive.
It’s quite bright. It might not rain today.

• As the past tense of may for requests:

He asked if he might borrow the car.
They wanted to know if they might come later.

• For very polite requests:

Might I ask you a question?
Might we just interrupt for a moment?

We use may have and might have to show that something has possibly happened now or happened at some time in the past:

It’s ten o’clock. They might have arrived now.[= Perhaps they have arrived]
They may have arrived hours ago. [= Perhaps they arrived hours ago.]





I have some doubts about modal verbs. I would appreciate if you could help me.

I read that the difference between may have and might have is that you use might have when you know that something is not true or did not happen. For example,"He came home alone yesterday. You shouldn´t let him do that; he might have got lost".
However, I also read that could have is used when you talk about a possibility although you know that something has not happened. For example, "You were stupid to go skiing here. You could have broken a leg."

My question is, can I use could in the first sentence and might in the second one without any change in the meaning? I can´t see the difference because the explanation seems the same in both of them

Thank you in advance.

Hi Red_Rach,

You are quite right: could have and might have are interchangeable in these sentences, but may have is not possible.



The LearnEnglish Team

Hello everybody, i'd love to know if it's correct to use "might have" in this following sentence to express "low probability" : "Samuel might have said something similar about some European masterpiece when he was in his thirties"?
Thank you

Hello paris-sorbonne

Your sentence is grammatically correct, but 'might have' expresses weak possibility more than probability. A paraphrase of your sentence is 'It's possible that Samuel said something similar ...' I suppose that be saying it's possible (instead of likely), one could draw the conclusion that you think the probability was low. But the modal verb in itself doesn't express this.

To clearly show low probability, I'd suggest using some kind of more explicit phrase. For example, 'It's unlikely, though not impossible, that Samuel said something similar ...' You could also leave out 'though not impossible' to make the sentence express very low probability.

Hope this helps you.

All the best


The LearnEnglish Team

Thank you teacher for your answer, i asked this question because in my exam i had this sentence and it was asked to use a modal verb to express low probability, so i could't think of another modal verb to express that...i'll wait for the correction then :)

as you mentioned in "past tense of may for requests", its related example was not clear for me and did not make sense. So, we had:

"He asked if he might borrow the car."
which type of conditionals are employed in the aforementioned sentence?
and also here:
"They wanted to know if they might come."

Obviously, you have mentioned that we can use modals (might, could, ...) in the second side of conditional sentences. But, we can observe that it also can be used in the first sentences of conditionals along with "if", too.

Hi hadi.khorand,

These are not conditional structures. In this case, 'if' has the same meaning as 'whether' and is used to ask an indirect yes/no question.

All the best,
The LearnEnglish Team

Hi The Crew and all the other friends,
I want to make some comments on modal expressions may/might/could have + v3 , also I want to ask you some examples. It would be very kind of you if I might get answer or a reply from you, thanks beforehand...

First of all I should say that I have been working as an english language teacher and trainning english language classes. I teach my students that
may have done/might have done and could have done have got a same meaning while mentioning a past possibility at a degree of % 50 certainity .

as an example
A: I cannot find my keys, where can they be?
B: I do not know exactly but you may/might/ could have dropped them in the car.
You may/might/could be right, let's check .

Are these three options correct ?

Also i teach my students that 'could have done' has another meaning in the past that means ' i had the chance or oppurtunity to do something in the past but i didn't do'
as an example
'Yesterday it was my day off so i could have gone to cinema but i chose to stay at home and slept all the day.'

Also i desire to write a sentence and want to get your oppinion about it

'By the end of this month, we may/might/could have sold half of the tickets.'

What's your oppinion about the sentence? Are the three options can be used interchangeably or are there any differences in meaning?

Thank you

Hello BlackNoah'sSon,

All three options (may, might and could) are possible in your example and have the meaning 'it is possible that this happened'.

As you say, 'could have' can also mean 'had the possibility but did not'.

I think all three options are possible in your last example. There is an implied condition here, I think, along the lines of 'if everything goes well then...' or 'if we work hard then...'



The LearnEnglish Team

Thank you Peter for your confirmation and clarification,

In order to leave a useful note for future search, I also want to point out another usage of 'might have done' which has meaning difference with 'may have done'. I mean these two modal patterns do not always have the same meaning.

'' Why did you do that madness with your car!? We might have had a car accident.''

I think in this context we cannot use 'may have had a car accident',

What do you think about this case?