8. Перепишите следующие предложения; подчеркните в каждом из них модальный глагол или его эквивалент. Переведите предложения на русский язык.

1. All you have to do is to mix the finely powdered substance in definite proportions.

2. Plastics can do a better job, often at lower cost.

3. Medicinal plants should be stored in a dark place protected from light.

4. Such substances may be classified as oily, pungent, acrid or astringent.

9. Переведите предложения.

1. Вы должны читать по-английски бегло.

2. Она уже прочла книгу.

3. Им следует наблюдать реакцию.

10. Прочитайте и письменно переведите текст.

Importance of Carbon Chemistry

1. It is well known that the element carbon plays an important role in the life on Earth. If all the carbon and carbon compounds were suddenly removed from the earth it would look like the surface of the moon. Many of the little everyday things would be quite impossible without the element carbon. In an ordinary pencil, for example, the inside of the pencil made from graphite which is an elementary form of carbon, the wood and the paint on the surface of the pencil are all of carbon or carbon compounds. The paper of this, book, the cover and so on are also made of carbon compounds. All of the clothes one wears including shoes cannot exist without carbon. If carbon, compounds were removed from the human body, there would be nothing left except² water and a small residue of minerals and the same is true for all forms of living matter³. Fuels, foods and many drugs .are mostly made of carbon compounds. In addition, many carbon compounds such as plastics to be connected with the life processes play a vital role in one is life.

2. There are nearly two million different carbon compounds to have been studied and described in the chemical literature with thousands of new ones, which are reported every year. Although there are 89 other naturally occurring elements, the number of known carbon compounds is many times greater than that of the known compounds which contain no carbon.

3. The very large and important branch of chemistry, which studies and investigates carbon compounds, is called organic chemistry. The name "organic" comes from the past when chemical compounds produced from once-living matter were called "organic" and all other compounds were called inorganic.

4. The importance of carbon chemistry for man is great. Every month several hundred new organic compounds are prepared. A few of these new compounds become important as medicines, plastics, textiles, solvents, food additives, cosmetics or some other products. A very few number may provide an important explanation of the mechanism of fundamental chemical reaction in the human body. Most, however, become laboratory findings and for the present, at least, have no practical application.

5. The preparation of new and different compounds through chemical reaction is called organic synthesis. The million or so organic compounds now known and characterized were synthesized in the laboratories of the world in the past 150 years.

6. Complex mixtures of hydrocarbon compounds containing only carbon and hydrogen occur in very large quantities in nature as petroleum and natural gas. Many other organic compounds are prepared from these materials after they are separated into their constituents. From the simplest hy­drocarbon, methane, come such products as plastic vessels, acrylic fibers, vinyl paints, etc.

.