К основным законам распространения звука относятся законы его отражения и преломления на границах различных сред, а также дифракция звука и его рассеяние при наличии препятствий и неоднородностей в среде и на границах раздела сред.
На дальность распространения звука оказывает влияние фактор поглощения звука, то есть необратимый переход энергии звуковой волны в другие виды энергии, в частности, в тепло. Важным фактором является также направленность излучения и скорость распространения звука, которая зависит от среды и её специфического состояния.
Task 1. Reading.
Read this passage and do the exercise below.
Native Americans
The first people to live in a land are called indigenous peoples. Sometimes these peoples are referred to as Indians or American Indians. This is because when Columbus had first landed in America, he thought he had sailed all the way to the country of India.
Native Americans lived throughout North and South America. In the United States there were Native Americans in Alaska, Hawaii, and the mainland of the United States. In the middle of the country lived the Plains Indians, including tribes such as the Comanche and Arapaho. In the Southeast area of the country lived tribes such as the Cherokee and the Seminole.
The Native Americans were grouped into tribes or nations usually based on the area they lived in and their culture such as their religion, customs, and language. There were hundreds of tribes throughout the United States when Columbus first arrived. Many of them are well known such as the Cherokee, Apache, and the Navajo.
Exercise 1: Do the following statements agree with the information given in the text? Write true or false.
1. American Indians were the first people to live in the USA.
2. Apache is a Native American Tribe.
3. Hawaii had a number of Native Americans.
4. Cherokee lived in the Northern area of the country.
5. Columbus thought that the country was called India.
Task 2. Dialogue.
Put the dialogue in order. Number the sentences.
Sue Could you swim when you were seven?
Sue Jim, can you swim?
Sue No, I can’t.
Jim No, I couldn’t.
Sue Could you play the guitar when you were seven?
Jim Yes, I could.
Jim Yes, I can.
Jim No, and I couldn’t play it when I was five but I can play it now. I’m very good. Can you play the guitar? Sue Could you swim when you were five?
Task 3. Grammar.
Fill in the blanks with could, can, couldn't, can't.
1. We choose our opponents. The teams will be matched randomly.
2. Adan and her mother open the door because it was locked.
3. Mary tried hard to persuade her friend but she change her mind.
4. you swim when you were 10?
5. He's amazing, he speak five languages, including Chinese.
Task 4. Writing.
Write about the main character in the book you have just read.
Descriptor A learner
• writes grammatically correct sentences;
• uses different grammar structures accurately;
• answers the questions.
1. Title of the book and author:
2.Who was the main character in the story?
3. What did the main character look like?
4. What problems did the main character have? How did the main character solve his or her problem(s)?
5. Would you have solved the problem differently? How?
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