1: was watching

2: started - were playing

3: was sitting

4: was playing - was reading

5: was sleeping - came

6: was ringing - were playing

7: was cooking - was watering

8: was driving - saw

9: was doing

10: were watching

11: went - was raining

12: were you watching - phoned

13: came - was having

14: saw - was wearing

15: broke - were playing

16: was waiting - arrived

17: were having lunch - rang

18: was having - rang

19: didn't go

20: did you do

21: arrived - was still sleeping

22: was watering - was chatting

23: were crossing - saw

24: was ringing - was taking

25: heard - was opening

1, was watching

2, started/ were playing

3, was sitting

4, was playing/ was reading

5, was sleeping/ came

6, rang/ were playing

7, was cooking/ was watering

8, was driving/ saw

9, was doing

10, were watching

11, were going/ rained

12, were you watching/ phoned

13, came/ was having

14, saw/ was wearing

15, broke/ were playing

16, was waiting/ arrived

17, were having lunch/ rang

18, was having/ rang

19, didn't go

20, did you do

21, arrived/ wass still sleeping

22, was watering/ was chatting

23, were crossing/ saw

24, was ringing/ was taking

25, heard/ was opening

_____________

$S+was/were+V-ing$

$S+V-ed/V_quy-tắc$