30. They don't know the entrance ______ the museum.

29. The dinosaur was covered ________ feathers. It looks ________ a bird.

28. This teapot was made ________ metal. And it's used ________ drinking.

27. Whose is that chair ________ three legs?

26. His father left for New York ________June 8, 2004.

25. I don't know if he ________ (come). As soon as he ________ (come), I'll ring you.

IV. 根据句意，用适当的介词填空。(5分)

24. I can't work out this problem. And I don't know who ________ (ask).

23. Mr Green ________ (teach) here since two years ago.

22. Where ________ the lost child ________(find) yesterday?

21. -What ________ clothes ________(use) for?

-For ________ (keep) warm.