Possibility

Possibility

Might and could are both used to say that something is possible. Look at these examples:

• This might not be a good thing to do.
  (= It is possible that this isn't a good thing to do.)
• You could be getting the flu.
  (= It is possible that you are getting the flu.)

With affirmative sentences we can use either might or could.

• You might be experiencing the first symptoms.
• You could be experiencing the first symptoms.

But with negative sentences we need to use might.

• This might not be good for her.
  NOT: This couldn't be good for her.