Speaking

Task 12. Fill in the gaps in the text with the proper words from the box. Then read and speak on the fact stated in the text. You may use the following phrases to link the sentences.

• It is fact that…

• As everyone knows…

• There can be no doubt that…

• It is common knowledge that…

• We must face the fact that…

• Apparently (obviously, evidently)…

• The reason for this lies in the fact that…

• This illustrates the fact that…

• To account for this fact…

chemistry	warming	greenhouse gas	gases	hydrocarbons	carbon dioxide	effects	carbon
(…)	(…)	(…)	(…)	(…)	(…)	(…)	(…)

There is sometimes some confusion about the difference between (1) and carbon dioxide, and to understand the distinction, you'll need to remember your (2) lessons. Carbon is the element that combines with oxygen to produce (3). For every one molecule of carbon, there are two molecules of oxygen (hence CO₂). Carbon on its own is not a (4), but often CO₂ is shortened to carbon for ease of reference, and this is the case with the сarbon аccount.

As well as carbon dioxide, there are other (5) (such as methane) which cause global (6). Collectively, they are known as “greenhouse gases” and in chemical terms, most of them are (7). For ease of comparing the warming (8) of each gas, we can convert other greenhouse gases into carbon dioxide equivalents.

Writing

Task 13 (A). Read the text below carefully and try to work out how it can be improved by means of linking words and phrases for now, for the time being, actually, besides, later on, comparatively, similarly, consequently, in fact, after all, to illustrate, as a result, on the whole, that is to say.

Task 13 (B). Then write a brief report about the increase of carbon dioxide in the atmosphere using the information from the text. You may take into consideration the following advice on writing a report.

A report contains facts and information which are often based on some kind of research and also may include suggestions. The key to writing a good report is to make the contents relevant and to organize it clearly. Here are some tips on writing a report:

• make sure you answer the question and include all the relevant information;

• plan your report before you start writing;

• use headings to make your report clearler;

• use appropriate expressions to give examples, to generalize and to link ideas;

• in your introduction, say what the aim of the report is and where information comes from;

• in your conclusion, summarize the main points of the report by means of the phrases The report summarizes the results of..., it also describes..., the report ends with a look at possible developments (solutions, studies)...

There is a growing concern about the environmental contamination caused by the burning of great amounts of fossil fuels and about the increasing expense of finding them and processing them into easily usable forms. During the last 100 years the amount of carbon dioxide in the atmosphere has increased, and there is evidence that this phenomenon may be due to the burning of fossil fuel. Use of biomass, which consists of plants or plant waste, would not produce excess carbon dioxide because the plants absorb the gas for their growth. Wood is not as concentrated a form of energy as fossil fuels, but it can be converted into a more energy-rich fuel called charcoal. Burning fossil fuel also releases acidic oxides of sulfur and nitrogen, which are deposited on the earth in rainwater. The clearing of forests, particularly in the tropical regions, also threatens to increase the amount of carbon dioxide in the atmosphere because the forests utilize carbon dioxide for growth.