1. These children bought Book Two last Saturday.
2. He is sitting on his teacher's chair now.
3. It doesn't snow here in July.
4. I think that they will be in the library in the afternoon.
5. I have been studying English for five years.
6. I moved to the city three years ago.
7. They have been discussing the problem for two hours.
8. Oleg can't speak to you now. He hasn't finished his lunch yet.
9. Nina has been working since 9 o'clock.
10. I have been working in the garden since 10 o'clock.