4. Answer the questions on the text:

1. How does the sun’s energy manifest itself?

2. What are the most ancient of man’s sun-activated processes?

3. How long has photo-electricity been known?

4. What can you say about the most fundamental of all thermal solar processes?

5. What is the most effective way to minimize the loss of energy from the sun heated surface?

6. What is the simplest collector of solar energy?

7. What are the potential and actual applications of solar energy?

8. What is a new way to generate electricity?

5. Translate the following sentences from English. Pay attention to the sequence of Tenses.

1. It is well known that the sun's energy to manifests itself as thermal, photo-electric and photo-chemical effects.

2. Most fundamental of all thermal solar processes are the simple fact that, when sunlight falls upon a surface of any kind, the surface becomes warmer than the surrounding air.

3. It was mentioned that a flat plate of blackened metal covered with one or more transparent sheets of glass or plastic was known to be the simplest collector of solar energy.

4. Physicists said that they discovered a new way to generate electricity directly from radiation, without going through the thermal cycles both nuclear and solar power.

5. We believe that solar radiation is an immense and inexhaustible source of energy our world possesses.

6. Researchers say they need to learn how to use solar energy cheaply and effectively to heat and cool our homes, produce fresh water from sea water, and to generate large blocks of electric power.

7. The scientists are sure that solar units probably continue to be relatively small and applicable only to special purposes such as irrigation and power production in isolated locations.

6. Change the following sentences paying attention to the sequence of Tenses. Translate these sentences

Model: She says that she will go to the laboratory. – She said that she would go to the laboratory.

1. Physicists say that they discover a new way to generate electricity directly from radiation.

2. We know that the air space between the surface and the glass is an effective prevention of heat loss by convection.

3. We notice that the extent to which the surface temperature rises depends upon many factors.

4. We learn that the distillation of sea water is another process to be accomplished by variations of the simple flat plate collector.

5. The teacher says that the production of salt by solar evaporation of sea water is probably the most ancient of man's sun-activated processes.

6. The scientists say that they present a few methods of solution of this important problem.

7. We know that our power station produces a great amount of energy.

7. Use the verbs in brackets in a proper Tense form

1. I told him that I (to wait) him in the corridor.

2. She said that she (to work) in this company for a long time.

3. He mentioned that he (to be interested) in my research.

4. I wondered whether the manager (to come) to see the results of our work.

5. I was sure she (to speak) English very well.

6. The students asked if the delegation (to arrive).

7. She said that she (to do) all the experiments yesterday.

8. They said that they (to try) to catch the 10 o’clock train.