21. They are looking for the girl and her dog that have lost the way in the forest.

22. The children often go swimming at weekends when they have much free time.

23. Someone who has looked for you for 5 days is waiting for you outdoors.

24. Five students whose test results are excellent will be awarded a present.

25. We moved to Paris where we lived for 6 years.

26. The last time I went to Sa Pa was in May when the weather was beautiful.

27. Lack of practice is the reason why I didn't pass the exam.

28. Yesterday I met Tom, whose son is cute.

29. I moved to a new town where trees are planted along the street.

30. I watched a wonderful film whose plot is quite complex.

III.

16. were

17. would have stopped

18. meet

19. had had

20. will travel

21. hadn't studied

22. had

23. didn't see

24. fitted

25. told