Here are the sentences converted into reported speech:

1. She said that she couldn’t find her umbrella.
2. They said that they were learning English then.
3. Tom said that his friend was coming the following week.
4. He said that he would help his mum with housework that weekend.
5. They said that they would overcome that difficulty.
6. My friend said that her father was a doctor there.
7. The boy said to his neighbor that he was going on holiday the next day.
8. The teacher told her students that they would have to finish all those exercises before the following week.
9. She said that she had come back there early the day before.
10. She said that she had broken the vase.
11. The boy said to the girl that he would never see her again.
12. He told her that she was his friend.
13. Johnny told his mother that he didn’t know how to do that exercise.
14. The children said that they were waiting for the school bus.
15. Mary said that her father had died a year before.
16. John said that he had finished studying his lesson.
17. Mary told her friend that she could not go to the movies with John.
18. Mary said that she would expect to see her the following Wednesday.
19. He said that he didn’t know what had happened.
20. She said that she had gone to the doctor the day before.
21. He said that he had a toothache.
22. She said that she would write him a prescription.
23. They said that they were going to the drugstore.
24. He said that the doctor had given him some pills.
25. She said that she went to the supermarket every day.