what is the difference between can could and may might

Can Used to express ability (to be able to do something) : I can make jewelry. He can't speak French. Can you open this jar? Used to ask for permission: Can I use your bathroom? Can I leave now? Can I raise the volume? Used to make requests or suggestions: Can I have more napkins? Can I have the bill? You can take this spot if you like. You can do whatever you want. Could (past form of can) Describes an ability that someone had in the past: I could swim when I was young. You could see the boat sinking. They could tell he was nervous. Often used in auxiliary functions to express permission politely: Could I take this jacket with me? You could borrow my umbrella. Could you please let me pass you? Could I get you more water? Used to express possibility: All of them could ride in the van. You could always stay at our house. Could it be true? This plan could really work out. May Used to ask for formal permission: May I come in? May I say something now? May I ask one question? Used to suggest something that is possible: She may agree with this plan. They may not be happy about what happened. It may shower tonight. Might (past form of may) Used to suggest a smaller possibility than may does (actually, might is more common than may in American English) : He might have finished it. I might go see a doctor. I might not come this time. It might be right. You might have lost it. The store might have been closed today.

In popular usage and speech, may and might are used interchangeably when referring to possibility and probability, but there is a slight difference between the two. May is used to express what is possible, factual, or could be factual. For example, He maylose his job.

can could you have

Could (past form of can) Describes an ability that someone had in the past: I could swim when I was young. You could see the boat sinking. They could tell he was nervous. Often used in auxiliary functions to express permission politely: Could I take this jacket with me? You could borrow my umbrella. Could you please let me pass you? Could I get you more water? Used to express possibility: All of them could ride in the van. You could always stay at our house. Could it be true? This plan could really work out.

Might (past form of may) Used to suggest a smaller possibility than may does (actually, might is more common than may in American English) : He might have finished it. I might go see a doctor. I might not come this time. It might be right. You might have lost it. The store might have been closed today.

May Used to ask for formal permission: May I come in? May I say something now? May I ask one question? Used to suggest something that is possible: She may agree with this plan. They may not be happy about what happened. It may shower tonight.