Mr. Pike gave you a lift. Did you thank him? => Did you thank Mr. Pike, whom gave you a lift?

Henry is a plumber. His tools were stolen. => Henry is a boy whose tools were stolen

He is a boy. We saw him at the bookstore. => He must be a boy whom we saw at a bookstore.

Mr. Brown can play tennis. He is over seventy. =>Mr. Brown  who is over seventy, can play tennis.

Dang Thuy Tram's Diary is a beautiful book. I've read it twice. =>Dang Thuy Tram  which I've read twice, is a beautiful book.

1. Did you thank Mr. Pike, whom gave you a lift?

2. Henry, whose tools were stolen, is a boy.

3. He is a boy whom we saw at a bookstore.

4. Mr. Brown, who is over seventy, can play tennis.

5. Dang Thuy Tram' Diary, which I've read twice, is a beautiful book.