下列句子合并为含有定于从句的复合句,帮忙看下这么改对吗,错的话说下原因?

下列句子合并为含有定于从句的复合句,帮忙看下这么改对吗,错的话说下原因?
The boy has come back.The policeman is looking for him.改好了是,The policeman is looking for him that has come back
The boy is our monitor.You talked to him yesterday afternoon.改好了是,The boy is our monitor that talked to your yesterday afternoon.
The beautiful woman is his mother.We met her at the theatre yesterday.改好是,The beautiful woman is his mother that met us at the theatre.
帮忙看下这么改对吗,错的话说下原因?