The book that/which/- you lent me is not interesting.
This is the hotel that/which was built last year.
The man who/that/whom/- you met yesterday is an actor.
He is the only student who/that understands English well.
The flowers which/that/- I love best are roses.
The pilot whose plane landed in a field was not hurt.
关系词在定语从句中作宾语时，可以省略。