May I leave now'? (Yes) , you may (leave) Can I leave now ? (No) , You cannot.. Must I leave now ? Yes, You must... Should I leave now ? No, you should not.. etc Just repeat the word used to form the question. May for request to do something. > May I sit here? May I go now? Can is normally about your ability in doing something ( not for request, but common in conversation).> Do you think I can lift this box ? Must > Need to do something > Must I see him again ? Should > used when asking someone's opinion > Should I tell him? Should I go? Should I bring my sister along Shall I go ? > used as a suggestion > Shall I bring my sister along ?Shall we throw a party for her? Can vs may > May I leave? Yes, of course you can , but you may not ( of course you have the ability to leave, but permission not given ( may not) > correct usage example

In common English, people use "can" and "may" interchangeably. But traditionally, "can" implies ability (you are physically able to open the door and walk away), whereas "may" implies permission. If the person asks "may I leave," then the safest positive answer is "yes you may" (or just yes). "Must" implies something beyond permission. For example, you have permission to leave your own house, but if there's a terrible storm outside, someone might say "you mustn't leave! It's too dangerous!" Note: In my opinion, "must" is becoming a bit old-fashioned in common use, especially in the US.

If the question is "May I leave?", then you want to answer using may not can. If the question is "Can I leave?", then you would use can. So like you have above; If the answer is yes, then you can say "Yes, you may leave." or more simply "Yes, you may." If the answer is no, then you can say, "No, you may not leave." or more simply "No, you may not."