MAY AND MIGHT

 Where's Peter?    He may be at school  (= perhaps he is at school)

                     He might be in class (= perhaps he is in class)

• We use may or might to say that something is a possibility. usually you can use both of them, although  might suggests a weaker possibility.

 He may be wrong / He might be wrong

The negative forms are may not and might not (mightn't).

He may not be wrong (=perhaps he is not wrong)

It might not be true (=perhaps it is not true)

Sometimes COULD  has a similar meaning to "may" and "might".

  The phone is ringing. It may/might/could be Tim

Study this example:

• They are sick.  This means that the speaker is sure that "they" are sick.
• They could be sick.  This means that the speaker isn't positive that "they" could be sick.
• They might be sick.  Again, thismeans that the speaker isn't positive that "they" are sick.
• They may be sick.  This means the same as above.  The speaker isn't positive that "they" are sick.

But couldn't  is different from "may not" and "might not". Compare:

It may/might not be true (perhaps it is not true)

It couldn't be true ( it is not possible that it was true)

• " May" and "might"  are also used to talk about possible actions or happenings in the future.

I don't know where to go on holiday this summer. I may/might go to Malta ( perhaps I will go to Malta)

Tim might not / may not come to the exam tomorrow ( perhaps he will not come )