19. Ответьте на следующие вопросы:

1.When did man first begin to apply petroleum? 2. How did ancient people use petroleum? 3. What factor has led to the development of modern petroleum industry? 4. How can one define petroleum? 5. Where does petroleum form and accumulate? 6. Does petroleum consist of different hydrocarbons? 7. What impurities does petroleum often contain? 8. On what factors does the odour of petroleum depend? 9. Is the colour of oil always dark brown? 10. What determines its colour? 11. What is the dependence of the colour of oil on its specific gravity? 12. Are all sorts of petroleum combustible? 13. Is there a clear explanation for the petroleum formation? 14. Do all scientists admit the organic origin of petroleum?

20. Перескажите текст, используя вопросы упражнения 19.

21. Запомните следующие слова:

oily – маслянистый remote – отдаленный

liquid – жидкость distinctive – отличительный, характерный

exclusively – исключительно to consider – считать, полагать

odour – запах molecular weight – молекулярный вес

to dissolve – растворять epoch – эпоха

Прочтите текст и озаглавьте его.

Petroleum is an oily combustible liquid. It is usually dark in colour and has a distinctive odour. It is much lighter than water and does not dissolve in water.

There are several theories of the origin of oil, as petroleum is often called. Many scientists consider that petroleum was formed in remote epochs by the decomposition of plant and animal organisms out of contact with air.

Like natural gas, petroleum is a mixture of hydrocarbons, only of higher molecular weight. Petroleum consists for the most part of liquid hydrocarbons, but there are gaseous and solid hydrocarbons dissolved in them.

Прочтите отрывок из текста и ответьте на вопросы.

Petroleum is an oily combustible liquid. It is usually dark in colour and has a distinctive odour. It is much lighter than water and does not dissolve in water.

1. What is petroleum? 2. What colour is petroleum? 3. Has petroleum an odour? 4. Does petroleum dissolve in water?

Закончите следующие предложения, выбрав один из предложенных вариантов.

There are several theories of … a) the discovery of oil;

b) the origin of oil;

c) the composition of oil.

Many scientists consider that petroleum was formed …

a) in remote epochs; b) not long ago; c) in 19th century.

Many scientists consider that petroleum was formed by …

a) the decomposition of plant and animal organisms in contact with air;

b) the decomposition of plant and animal organisms out of contact with air;

c) the decomposition of plant and animal organisms in contact with water;

Прочтите два варианта одного и того же отрывка. Найдите расхождения между вариантами.

1. Like natural gas, petroleum is a mixture of hydrocarbons, only of higher molecular weight. It consists for the most part of liquid hydrocarbons, but there are gaseous and solid hydrocarbons dissolved in them.

2. Like natural gas, petroleum is a mixture of hydrocarbons, only of lighter molecular weight. It consists of liquid hydrocarbons. Gaseous and solid hydrocarbons do not dissolve in them.