1. The student who is dressed in white is her daughter.
→The student dressed in white is her daughter.
2. I have read plenty of books which were written by Lu Xun.
→I have read plenty of books written by Lu Xun.
3. His nephew, who was lost at sea when he was fifteen, had been his only relative.
→His nephew, lost at sea when he was fifteen, had been his only relative.
