Interested in Language
1. Relative clause: This is the who broke the window.
2. Reduced relative clause: The is the man broke the window. ("who" is omitted)
3. Relative clause: This is the girl who has killed her mother.
4. Reduced relative clause: ....
5. Relative clause: This is the girl who had killed her mother.
6. Reduced relative clause: ....
As you see in number 2 if we write a reduced form of a relative clause we omit the relative pronoun.
But what if it's in present or past perfect? How should we rewrite number 4 and 6? I mean should we omit "who"?