ответить на вопросы: how did you first meet? what was your first impression them? what do you like about them? what don't you like about them? what do you have common? how do you differ? why did you become such close friends? will you be friends for life? what do they look like? what are they like as a person? what special talents and abilities do they have? what kind of clothes do they wear? what's their job? what's their family like? what are their hobbies and interests? what do you do and what do you talk about when you're together?

Попробуй написать о своей лучшей подруги или спроси у нее лично, если хочешь можешь написать по русский, я или другие тебе перевидем. 

Dear Mr (Mrs)
I'd like to participate in the program of exchanging students. Here is a number of reasons for why I submit an application.
Firstly, I'm very interested in culture, history and people of Canada. The program will give me a good opportunity to compare my actual knowledge of Canada and the reality. I suppose, that canadian society is effective in diverse directions: state institutions are transparent, industry is well-developed, the standart of living is high, and people are thinking about their future. I want to know how Canada achieved it and to bring this knowledge backin Russia to apply it here. I firmly believe my generation can do a lot for Russia.
Secondly, in my point of view, both of this countries are similar. Russia and Canada are countries of multicultural diversity. Both of them are huge, I ment the size of territory and the population. Canadians and Russians have a rich history, unique culture and outstanding technological achievements. Student exchangement can bridge the gap between our countries and make all us better.
To sum up, when I'll come back, I'll have my own impressions and the image of Canada, my own experience that will contribute to a better understanding of cultures and that will make our world a bit safer.

ВОЛНЫ И ВОЛНА - ДВИЖЕНИЕ

Мы видим волны на воде почти каждый день, мы используем световые волны, чтобы увидеть волны на воде; мы слышим звуки с звуковых волн. Волна - движение везде. Водные волны, световые волны, звуковые волны, любые волны имеют одну общую черту. Они передают энергию через среду посредством колебаний частиц, но среда в целом не изменяется и не смещается. Число полных колебаний в секунду называется частотой волнового движения. Расстояние между вершиной одной волны и вершиной следующей (или между основанием одной волны и основанием следующей) называется длиной волны. Чтобы найти скорость волнового движения, мы умножаем частоту на длину волны. Это важное уравнение верно для любых волн.

1) What types of waves are there?
2) How do waves transmit energy?
3) The frequency of the wave movement is it?
4) What is Wavelength?
5) How to find the speed of wave motion?