Allow me to start with an anecdote! I remember many times as a child asking my father Can I have an ice cream?; Can I watch television?; Can I get down from the table? etc. Each time I was happy to hear the answer Yes, you can! - only to be stopped short the next second by the continuation .. but you may not!
Not many people these days reject the use of can in asking permission, but May I .. certainly sounds politer and is therefore better in some formal situations.
If you have looked at the pages on the other modal verbs, you may expect may to be quite troublesome to use correctly; and you would be right! In the previous paragraph we saw its use in asking permission, and in the the first sentence of this paragraph we see an example of its second common function - in expressing possibility: you may expect .. . Test your knowledge on may and its associated word might by looking at the following quiz questions:
Fill in the blanks in the following sentences. In each case you should express the idea of permission to do something:
Are any of the following sentences not possible?
Why is may used in the first sentence below, but allowed to in the second?
Are there any problems in these two sentences?
Is there a difference between these sets of two sentences?
What is the difference between these two sentences?
What does may mean in the following sentences?
What does might mean in the following sentences?
What are the two meanings of might in the following sentence?
This is a polite request for permission to do something.
This is a request for someone else to do something. It has to be Would or Could you ..
This means: It is possible that I will be late tomorrow.
This is a polite request for permission to be late tomorrow.
The question should be expressed in one of the following ways, depending on what you want to say:
This is the expression of my hope that you will never be late.
More likely is: I hope I will never be late again.
In the first sentence above, may is used, but allowed to in the second. This is because in the first sentence I am asking someone for permission to do something, and in the second sentence I am asking about rules. Here are two more examples:
There is a problem in the first sentence. All the other modals and auxiliaries can be combined into one word (e.g. mustn't, oughtn't, haven't etc.), but for some reason we can't do this with may and not.
If you say may, you think there is a greater chance of being late than if you say might. So:
* The percentages are to show the relative possibilities expressed by the two words - don't taken them as exact!
In the second pair of sentences may and might are in reported speech and can be used by careful speakers to convey different meanings:
For many native speakers the distinction would be too subtle and they would interpret the sentences as meaning the same, i.e. he could possibly lose his sight.
This means there is a possibility that he is not right.
This means that is no possibility that he is right.
In this sentence may means will.
In this sentence may has the function of introducing the second clause beginning with but. Translated it means: Ok, I agree that he is very clever, but ..
The expression may as well gives this sentence the meaning: There is no point in staying - I will go home. or There is nothing better to do than to go home. Another example is: You may as well tell me - I'm going to find out anyway.
This means that there is a possibility he will ask to use your computer.
This implies, thanks to the exclamation mark, that he has used your computer, but without asking, and you are annoyed about this. The stress would be on the word ask. Another example is: You might have told me she's divorced!
Translated, this sentence means: It is true that he paid for the computer but it would have been good if he had asked before ..
If your brain is addled after these explanations then take comfort in Burchfield who writes: "I can see how easy it is to confuse the roles of 'may' and 'might' when in some circumstances they are more or less interchangeable." The New Fowler's Modern English Usage (Oxford 2004)