1. Look through the following text and find the answers to the given questions:

1. Who eats plants?

2. What is the form of carbon in the Earth’s crust?

3. What energy is used by green plants and algae and what do they do with it?

4. What are the ways of forming carbon dioxide?

5. How are human activities estimated now?

6. Why is hard now to estimate them?

It is known, that carbon, like water, cycles from the Earth into the atmosphere and back again. Green plants and algae use the sun’s energy to convert carbon dioxide (and water) into carbohydrates. The plants are eaten by animals, including people and fish, who exhale carbon dioxide. It was discovered that carbon dioxide is also formed by decomposition of dead animals and animal wastes by microorganisms. The carbon dioxide passes into the atmosphere and is again used for photo synthesis. An equilibrium also exists between carbon dioxide in the atmosphere and dissolved carbon dioxide and H2CO3 in oceans and lakes. In addition it was estimated that much carbon is stored in the Earth’s crust in the form of fossil fuels – coal, petroleum, and natural gas – and in the form of limestone and coral. Since the middle of the nineteenth century, it has been observed that the production of carbon dioxide by the combustion and the decomposition of limestones is increasing rapidly. In addition, it has been proved that destruction of tropical forests is reducing the quantity of carbon dioxide used up by photosynthesis. Human activities have now reached a scale where interference with the natural carbon cycle may well be significant. The longest continuous records of the concentrations of carbon dioxide in the atmosphere unfortunately were made only in 1958, and therefore it’s hard to be sure how harmful human activities have been since that time.

2. Read the text again and entitle it. Then divide the text into logical parts, give titles to all of them thus making a plan.

3. Write out all the sentences, expressing the main idea(s) of each logical part.

4. Condense the sentences of the text where possible.

5. Write an abstract to the text in your own words using the plan and the sentences you’ve written out and condensed.

Remember:

1. An abstract is an introduction of a reader into the matter.

2. An abstract is much shorter than a summary.

3. Points in an abstract are more generalized than in a summary.

Text

1. Read the text attentively. Try to understand all details. Use a dictionary if necessary.

Sulphur dioxide

Where does sulphur dioxide come from? Almost all the sulphur dioxide in the air comes from industrial sources. Industrial smelters, which obtain metals from sulphide ores, produce tones of sulphur dioxide daily. Half of the output of sulphur dioxide comes from the burning of coal. All coal contains between 0.5 and 5 per cent sulphur.

sulphur in coal + oxygen in air = sulphur dioxide

The sulphur dioxide escapes up chimneys into the atmosphere.

Worldwide, 150 million tones a year are emitted. The emission is growing as countries become more industrialized. Most of the coal is burned in power stations. These are always situated in the densely populated regions where the demand for electricity is high and where there are plenty of people to breathe in the sulphur dioxide.

What harm does sulphur dioxide do? Sulphur dioxide is a colourless gas with a very penetrating and irritating smell. It is poisonous; at a level of 0.5%, it will kill. The immediate effects of inhaling sulphur dioxide are coughing, chest pains and shortness of breath. Sulphur dioxide is thought to contribute to bronchitis and lung diseases.

What can be done about it?

• Tall chimneys carry sulphur dioxide away from factories. Unfortunately it comes down to earth again as acid rain.

• A number of processes for removing sulphur dioxide from the emission of power plants are being tried (see below).

SUMMARY NOTE

Factories and power stations burn coal, which contains sulphur. They send sulphur dioxide into the air. Metal smelters oxidize sulphides to sulphur dioxide. Sulphur dioxide causes bronchitis and lung diseases. In the upper atmosphere, it reacts with water to form acid rain.

2. Make a plan of the text. Discuss the text according to the plan.

3. Retell the text in short according to your own plan.

4. Discussion.

- How would you rate the quality of the air you breathe: good, fair, or poor?

- What are the major sources of air pollution in your area?

- What is the quality of indoor air where you live and study?

Text

1. Read the text attentively. Try to understand all details. Use a dictionary if necessary.