16. They were working when the boss came in
17. When Carol got to the bus stop, the last bus had left
18. I went to see the dentist after I had made an appointment
19. The workmen finished before the new owners had moved in
20. When the police arrived, the burglar had escaped
21. It was such a heavy rain that Laura walked to the office
22. By the time the police arrived, the robbers had gone away
23. I was having my breakfast when the phone rang
24. I took a taxi because I had missed the bus
25. When she came, I was having my dinner
26. When she was having her breakfast, the phone rang
27. When we arrived, David had gone home
28. After we had lunch, we went for a walk by the river
29. I began studying English 5 years ago
30. We last saw him in 2002
Chúc bạn học tốt ^_^ Nhớ vote cho mình 5 sao và cho mình trả lời hay nhất nhé =))
