13. We are very interested in the problem . It has been discussed in class .
the problem which we are very interested in has been discussed in class .
14. Lung cancer is very dangerous . Million of people died of it .
Lung cancer of which million of people died is very dangerous
15. I like standing at the window . I can see the park from the window .
I like standing at the window from which I can see the park
16. The woman lives next door to me . You gave place to her on the bus .
The woman to whom you gave place on the bus lives next door to me
17. The examination lasted 2 days . I was successful in this exams .
The examination in which i was successful lasted 2 days
18. This is the result of our work . I'm pleased with it .
This is the result of our work with which I'm pleased
19. Mr Brown is the man . I'm responsible to him for my work
Mr Brown is the man to whom I'm responsible for my work .

20. This snake is dangerous . I'm afraid of it .
This snake of which i am afraid is dangerous
21. There are a number of factors . We have no control over them .
There are a number of factors over which we have no control