can we make friendship wiyh our x-bf/gf???

And why not? After we closed a relationship with someone, we should also leave behind all the bad memories and start a new friendship. You learned from that relationship anyway so why not start a new relationship as friends and from there you can learn from each other more things that will and can help you in future relationships. Exes are one of the people who already knows you and most of them even understand you. They know your weakness and your strength. And I don't think letting go of that kind of person just because of a bf-gf relationship didn't work out is stupid.