Expressing permission : May and Can

 May

• Formal permission: "May" is generally considered more formal and polite when asking for or giving permission. It's often used in official or polite contexts.
  • Asking for permission: "May I borrow your pen?" (Very polite)
  • Giving permission: "You may leave the room now." (Formal)

Can

• Informal permission: "Can" is more common in everyday conversation and informal situations.
  • Asking for permission: "Can I use your phone?" (Informal)
  • Giving permission: "You can sit here." (Informal)

Key Differences and Usage Notes:

• Formality: The main difference is the level of formality. "May" is more formal, while "can" is more informal.
• Asking for permission: Both "may" and "can" can be used to ask for permission, but "may" is considered more polite.
• Giving permission: Both "may" and "can" can be used to give permission.
• "Could" for polite requests: While "could" is often used for polite requests, it's not typically used for formally granting permission.

Examples to illustrate the difference:

• In a classroom:
  • Student to teacher: "May I go to the restroom?" (More formal and polite)
  • Teacher to student: "You may go to the restroom." (Formal)
• Between friends:
  • "Can I borrow your car?" (Informal)
  • "You can borrow it tomorrow." (Informal)

In summary:

If you want to be very polite or are in a formal situation, use "may." In most everyday situations, "can" is perfectly acceptable.

Keynotes:1.  Maybe  is an adverb meaning "perhaps". 

                      Example : Maybe Linda is sick. Linda may be sick.

                 2.May not and can not are used to deny permission.

                      Example: You can not joke here.