Plural marker for personal pronouns
We are students. 我们是学生。
They like reading. 他们喜欢读书。
Combines 亻 (representing people) with 门 (symbolizing a group). Originally referred to a crowd passing through a gate, now used as plural marker. 由"亻"（表示人）和"门"（门）组成，本义指一群人通过门，现用作复数标记。