Ответ:
1. arrived, was writing
2. was making, went
3. realized, were travelling
4. were looking, saw, What were you doing?
5. were playing, heard, hid, took
6. was walking, stepped, fell
7. was reading, heard, went, opened, didn't recognize, wasn't wearing
8. came, were sitting, was doing, was knitting, were reading
9. Why did you interrupt me?; was having
10. arrived, was waiting
11. was, had to, was enjoying
12. was, knitted
13. were watering, began
14. found, was digging
15. was swimming, stole, had to
16. was, was practising
17. met, was working