当我们谈论某人时，“他们”已经常用作单数代词，但我们不知道是谁
https://www.npr.org/2021/06/02/996319297/gender-identity-pronouns-expression-guide-lgbtq
.....
"They" is already commonly used as a singular pronoun when we are talking about someone, and we don't know who they are, O'Hara notes.
