@ May is used to make a polite request
ex : May I go to the toilet ?
( it means that somoene have a polite request and asking permission to another person to give permission)
@ May is used to give permission in formal
ex : You may check your score in your email address
( it means that someone giving permission with well to another person)
@ Ability / Possibility
ex : You can trust me if I can keep your secreet
( it means that someone can trust another person with ability the person have)
@ Asking Permission
ex : Can you lend me some money ?
( it means that someone asked if we need something from another person)
ex : I will be back to you (future)
( it means that someone giving promise to back)
ex : I will do that for you if you like
( it means that someone will do anything if somebody need to help)