such and such
this and that
and so on
A: Who was that so-and-so you were talking to?
A：你刚才在跟那个谁说话？
B: Just some so-and-so from the street.
B：就是街上的一个熟人而已。
1) 指代不认识或不想说名字的人
2) 指代不确定的事物
3) 用于避免重复提及
1. 某人，某事
noun
1. A person or thing that is not specifically named.
Synonym: such and such