Ответ:

1. The concert began at 5 o'clock.  

2. They grew flowers in their garden.  

3. Mike came home early.  

4. When we met, we spoke about our work.  

5. My sister went to the cinema last week.

6. My friends brought me interesting books.  

7. I knew the subject well.  

8. I left Moscow in September.  

9. They made a few mistakes when they were speaking English.  

10. Nick did his homework last evening.  

11. She had lunch at noon.  

12. Tom read the newspapers in the evening.  

13. My friend found his work too easy.  

14. Helen swam very well.  

15. He gave promises but seldom kept them.  

16. We put our books on the shelf.  

17. In cold weather, we put on warm coats.  

18. Mary took her younger sister to school.  

19. These students knew English grammar well.  

20. He told us funny stories.

21. Nick's house stood in a big street.  

22. He knew what to do.  

23. She ate only vegetables.  

24. My friend spoke two foreign languages.