6.　　　 have … lived

5.　　　 to receive

4.　　　 weren’t listening

3.　　　 are sweeping

2.　　　 using

1.　　　 have taught

28. She doesn't know what_________ (do) and where__________ (go).

27. Would please tell us how___________ (make) the watch ________ (work)?

26. The radio__________ (use) once in a week in our class. 　It____________ (not use) yesterday because there was something wrong with it.

25. The old man often_________ (tell) the children a story in the evening. This evening he ________ (tell) two stories.