2. … means that no matter how a substance is changed, what it is made up of it will always stay the same.

1. Where is Kolya? — Не is at the lecture.
2. Father goes to work every day.
3. Yesterday father was at work and mother was at home.
4. Yesterday I went to the library, I borrowed a very interesting" book at the library.
5. Katya was sitting at the table. There were books and exercise books on the table. Her father went up to the table and put a vase on the table. He put some flowers into the vase.
6. Yesterday we went to the exhibition. We saw a lot of paintings at the exhibition.
7. Where is Tom? — He is at the stadium. He always goes to the stadium on Sunday. And his sister goes to the swimming pool. She is at the swimming pool now.
8. Do you like to go to the theatre?
9. When we came to the railway station, we put our things on the platform and sat down on a bench. Mother went to the shop and bought some lemonade.
10. At the lesson yesterday the teacher said to me, "There are two mistakes on the blackboard. Go to the blackboard and correct the mistakes!"
11. Were you at the concert yesterday? — No, we worked at the library and then we went to the park. We played in the park and then we sat on the grass,
12. There are not so many children in the yard today.
13. There are so many students at the lecture today. 

Guy Fawkes Day. November 5th is Guy Fawkes Day in Britain. All over the country people build wood fires, or "bonfires" in their gardens. On top of each bonfire is a guy. That is a figure of Guy Fawkes. He was one of a band of conspirators who wanted to blow up the Houses of Parliament and kill King James I and his ministers. However, the plot failed, Fawkes was caught on the 5th of November 1605. The conspirators were executed and Britain has celebrated Guy Fawkes night then. Before November 5th, children use their guys to make money. They stand in the street and shout "Penny for the guy". Then spend the money on fireworks.