a long-separated old friend的用法和样例：
- The first time meet, can handclasp, have the old friend that meet again after a long separation only, ability can be embraced each other, flap the shoulder of the other side.
- She's an old friend(= I have known her a long time).
- She's an old friend of mine(= I have known her for a long time).
- She is visiting her family after a long separation.
- After a long separation, they held a glad meeting.