Cấu trúc áp dụng:

When/ While + S1 + was/were + V-ing + O, S2+ V-ed2

=> diễn tả một sự việc đang xảy ra thì có một sự việc khác chen vào

While S1 + was/were + V-ing, S2 + was/were+ V-ing

=> diễn tả hai sự việc đang diễn ra tại cùng 1 thời điểm trong quá khứ

1, phoned (past simple tense); were playing (past continuous tense)

2, were playing; suddenly began

3, was working; were swimming

4, was waiting; saw

5, were taking out; gets

6, was putting one; was polishing

7, were you doing

8, listened; was explaining

9, was sitting; didn’t answer

10, was practicing; came

11, were doing; were lying

12, was filling; ran

13, saw; was still wearing

14, were dancing; broke

15, was driving; saw; was watching; stopped; got; was getting; ran; went; was getting; appeared; sitting; started; didn’t move; jumped; shouted; barked; started; followed; saw; were bleeding

16, was going; heard

17, saw; didn’t see; was looking