A: Who served you yesterday?#
B: The man who is standing behind the counter.#
C: I served him. He is the man who I served yesterday.#
A: Which book did you buy?#
B: The book which is on the counter.#
A: Which books did you buy?#
B: The books which are on the counter.#
A: Which dog is yours?#
B: The dog which is carring that basket.&