Pay attention to the prepositions

Dirty the air with gases, to poison the water with chemicals, in various ways, on the land, in the water, to fill the air with noise, one of the problems, destruction of the ozone layer, harmed by pollution, pollution of soil, for growing crops, brings ugliness to our naturally beautiful world, from cars, for millions of people, job for people, for the growing of crops, the amount of pollution, from radioactive substances, from nuclear weapons, are produced by a variety of electronic devices, exposure to large amounts, in reproductive cells, in the atmosphere.

IV. Read and give a summary of the text.

Radiation.

Radiation is an invisible pollutant that can be highly dangerous. Nuclear radiation comes from radioactive substances, including waste from nuclear weapons testing and from nuclear power plants. Small amounts of electromagnetic radiation are produced by a variety of electronic devices including computers, lasers, microwave ovens, TV sets, and X - ray machines.

Scientists have not determined exactly what effects small amounts of radiation influence people. But exposure to large amounts can cause cancer and harmful changes in reproductive cells.

International agreements ban most testing of nuclear weapons in the atmosphere. Such regulations have helped to eliminate the major sources of radiation. However, the amount of radioactive waste is constantly increasing. Scientists г.р£ studying the ways to eliminate these wastes safely and permanently.

V. Grammar. Согласование времён.

Transform the sentences according to the models to practise the use of the sequence of tenses.

a). Model: They are listening to music.

I knew that they were listening to music.

1. They are running the commercial TV music. 2. These radio stations are competing with each other. 3. The children are playing computer games. 4. They are writing a composition. 5. They are playing football.

b). Model: The boy is interested in history.

I was sure that the boy was interested in history.

1. The newspaper is delivered to him. 2. The film is watched by them. 3. He is busy. 4. She is glad to meet them. 5. The money is spent by them.

c). Model: They left for Moscow.

I hoped that they had left for Moscow.

1. Ann helped her parents. 2. She wrote a letter. 3. The boy studied the English language. 4. She cooked the dinner. 5. He bought the bread.

d). Model: They will go home.

I thought they would go home.

1. You will ask him. 2. They will be late. 3. He will go to the swimming pool. 4. She will bring the book. 5. They will come on Saturday.

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