=>
1. There are eighteen different kinds of penguins which live south of the equator.
2. Thank you very much for the present which you sent to me.
3. This is Mrs. Jones, whose son won the championship last year.
4. The bus crashed into a queue of people, four of whom were killed.
5. The man never forgot the day when he went to the interview.
6. Mary, whose boyfriend didn't turn up, ended by having lunch with Peter.
7. He paid me $5 for cleaning ten windows, most of which hadn't been cleaned for at least a year.
8. We was badly treated in prison where they fed us on dry and moldy bread.
9. The chair which I was sitting in suddenly collapsed./ The chair in which I was sitting suddenly collapsed.
10. The bed which I slept on has no mattress./ The bed on which I slept has no mattress.

which -> đtqh chỉ vật

who -> đtqh chỉ người

whose -> sở hữu

giới từ + whom/which