Chia động từ trong ngoặc với dạng đúng, hoàn thành câu

15. Before Mary (go)……………….. to work yesterday morning, she (lock)……………………..all the doors.
16. She couldn’t do the exam because she (not / prepare)………………………..for it carefully.
17. By the time he got up, it (snow)…………………………….for 2 hours.
18. Tom (join) …………………the army after he (leave) …………………………….school.
19. Peter said to the teacher that he (not / do)…………………………… the homework.
20. As soon as Jane (complete)…………………………the task, she (hurry)………………to the market.
21. After he (get) ………………….. to his office, he turned on his laptop and checked his emails.
22. When they came, we (wait)…………………….for him for 2 hours.
23. When she (arrive)…................. at his house, she (find).……..........… that he (leave)........................................ a
few minutes before.
24. Before Tommy met me, he (do)……………………. nothing.
25. Yesterday I was sorry that I (hurt)……………………. him.
26. They (tell) …………..her that they (not / meet) …………..………..her before.
27. When she (realize)…………………. her mistakes, she apologized.
28. When I (meet)……………my cousin 2 weeks ago, he told me that he (just / return)……...… from the South