Two other important modal verbs are may and might. The two are used interchangeably in standard American English to express probability or possibility:

–You may be wrong.
–You might be wrong.
–The attorney might be late.
–The attorney may be late.

The past form is expressed as follows:

modal (may/might) + have + past participle

–I may/might have left my glasses in the restaurant.

NOTE: Must can also be used to express probability:

–The plane must be leaving now.

Examples of May and Might: Usage

• I might be late for dinner.