DET-POSS
(代替 his or her，而不指明是男是女;有人认为这种用法不对)
You use their instead of 'his or her' to indicate that something belongs or relates to a person without saying whether that person is a man or a woman. Some people think this use is incorrect.
例句
Every member will receive their own 'Welcome to Labour' brochure.
每个党员都将收到一本名为《欢迎加入工党》的小册子。
But anyone looking for income from their investments is in a much worse state.
但是，那些指望靠投资获取收入的人境况更为糟糕。