16. __Were you watching______(you/watch) TV when I called you?
17. Ann __was waiting______(wait) for me when I__arrived______(arrive).
18. I __ wasn't driving_____ (not/drive) very fast when the accident__ happened______(happen).
19. He__was playing______ (play) the guitar outside her house when someone opened the window and___was playing_____(throw) out a bucket of water.
20. Daisy__was looking ______ (look) at the flowers when the thief__came______(come) up behind her and _snatched_______ (snatch) her handbag.