1. The book (which) I need is one the top shelf.
2. The girl (that/who) I met at the party is very friendly.
3. This is the station where Paul lost his suitace.
4. I don't know the woman whose son is waving at me.
5. 12th December is the day when I got married.
6. The reason why these dresses are so expensive is that they are made by hand.