分类——根据给定的场景，选择合适的短语。
场景：在公共场合看到老朋友。
1. Hi! Long time no see!
2. Hey! It's nice to run into you here!
3. Oh my gosh! I can't believe it's you! How have you been?
4. Well, well, well, look who it is! How's life treating you?
5. Hey there, stranger! How's everything going?