Can = Are you able or capable to do something? "Can you pickup some milk at the store on your way home?" Will = An action has not happened yet but might eventually. "Will you bail Joe out of jail?" "Will you do this? Will he do this?" May=Are you allowed to do something? "May(am I allowed) I go to the bathroom?" Might=In American English, I don't hear "might" being used often for permission. In Queen's English, you might hear, "Might I go to the cinema?(undecided or using similarly to "may I?")