Request and Promise

All the transactions we do can be classified into two major groups. One is the 'Request' and the other type is the 'Promise'. When we request something from the other person, we promise something else to be done immediately or in future. Sometimes it so happen that we request something for the promise which we had done earlier. We make promises for the requests which are to be done immediately or in the future. We do make promises for the requests already made.