Длинна волны в воздухе 20 см при скорости распостронения звука в воздухе 340м/с. Найти скорость распостронения звука в веществе если при той-же чистоте колебаний длинна волны станет 1 метр.

) Read the letter and say what Martin’s dream is:

London

Great Britain

20th of September

DearLena,

I am Martin Oldfield. I’m Jim’s friend. I live inLondon. Last summer I visitedRussia. I was inSt Petersburg. I spent two weeks there. We went sightseeing. We traveled on a comfortable bus round the city. But best of all I enjoyed the palaces which are situated near St Peter. We were in Pavlovsk, Pushkin and Peterhof.

There is the most interesting, great and beautiful palace in Peterhof. It was amazing to see so many fountains there. The guide told us a lot of stories and legends about them. It was interesting to listen to him. After the trip we returned to the city by ship. It was fantastic.

I was very happy to visitRussia. It helped me decide to study the Russian language. I would like to learn more about Russian history and literature. I like studying languages. I know a little French and German. And I can write fairy tales and short poems in English. My dream is to become a famous writer one day!

Do you have any hobbies? Do you like to travel? And how did you spend your summer?

Best wishes,

Martin

Complete the sentences. Use the information from Martin’s letter.

1. Peterhod is …

2. They visited…

3. It wasn’t boring…

4. The guide told them …

5. Martin would like to learn …

6. Martin’s dream is to become …