4. Answer the following questions:

1. How was native asphalt obtained in ancient times?

2. Where were large sources of native asphalt found?

3. What was asphalt used for?

4. What does the amount of asphalt in a crude oil depend on?

5. How is the crude oil transported to the refineries?

6. What processes are used in the refining of asphalt?

7. What is done to form a stable waterproofed base course?

Language focus

5. Build derivatives from the words below and translate them:

To vary – adj.; to resist – n.; to stabilize – n.;

to continue – adj.; to crack – n.; to coat – n.;

to extract – n.; to refine – n.; to form – n.;

stable – n.; proper – adv.

6. Match the following words with their synonyms:

a) to contain, to obtain, amount, to remain, to bind, course, to separate, way, to apply, fraction, to aid.

b) quantity, to get, to involve, method, to connect, to divide, layer, to help, to stay, particle, to use.

7. Put the correct forms of the words into the sentences:

Nature works its wonders

Sir Waller Raleigh ___________ on the island of Trinidad in 1595 and stayed there long enough to obtain a ____________ ofasphalt. The asphalt he used was a native asphalt ________ from an asphalt lake a short distance from the shore of the Gulf of Paria and was similar to that __________ by the ancienls. Hundreds of thousands of tons of asphalt have been _______ from the Trinidad lake without any sign of loss. As the material removed, pressure deep in the earth ________ more of the heavy residue to the surface, where nature continues its ____________ process. The natural asphalt ________ from the lake ________ many impurities and foreign matter such as water, fine sand and vegetation. To produce a _____________ paving material, these impurities have to be _________; therefore a refining process is necessary.

to land to supply to take to use to remove to force to refine to remove to contain to suit to remove

8. Translate from Russian into English:

1. Асфальт является природным материалом, получаемым из нефтяных скважин.

2. Сырую нефть транспортируют на нефтеочистительные заводы, где её разделяют на различные составные элементы.

3. Количество асфальта в сырой нефти зависит от её плотности.

4. Чем выше плотность сырой нефти, тем выше содержание асфальта.

5. При очистке асфальта используется два метода: метод паровой и вакуумной дистилляции, а также метод экстракции селективным растворителем.

6.Укрепление грунта или заполнителя асфальтом широко используется при строительстве дорог и аэродромов.

7. Тонкое покрытие асфальтом вокруг частиц грунта обеспечивает высокую степень водонепроницаемости основания дорожной одежды.