everyone 用himself 还是themselves?

everyone多指单数，但在反意疑问句的时候，反意疑问部分的主语要用they

根据语法是两种情况都可以
但现在为了避免引起"性别歧视"争论,尽量都会用themselves
就像chairman都会说成chairperson

themselves
薄冰英语语法

两种情况都有
看语境

Everyone is enjoying themselves.