1.   ..., who is a policeman

2.   We decided not to swim in the sea, which looked rather dirty

3.   The new stadium will be opened next month, which holds 90000 people

4.   John is one of my closest friends, whom I have known for 8 years

5.   That man over there is an artist, whose name I don't remember

6.   The storm causes a lot of damage, which nobody had been expecting

7.   This postman was late this morning, who is nearly always on time

8.   We often go to visit our friends in Bristol, where is only 30 miles away

9.   I went to see the doctor, who told me to rest for a few days

10. Thank you for your letter, which I was very happy to get

12. I looked up at the moon, which was very bright that evening