1. Определите функцию "it" и переведите предложения на русский язык.

A. 1.It is to be known that there exist many sources of energy in the world.

2. It is one of the oldest bridges in New York.

3. The energy of a body may be measured in either of the two ways: 1) by the work which it is capable of doing; 2) by the work which has been done upon it to bring it into condition in which it possesses energy.

4. It is necessary to maintain a given, constant mass of gas at constant temperature and observe how the changing of pressure affects the volume to be occupied by this mass of gas.

5. Adhesion is the attraction between two surfaces in contact. It depends upon the areas in contact and is independent of the pressure.

6. But why had Faraday's previous experiments failed? It was because his magnets, wires, and coils had been stationary. It was only when the magnet was moving that an electric current was generated.

7. It should be recognized that computers are capable of doing repetitive operations.

8. A third mode of transference of heat is known as radiation. It is the process by which the heat of the sun reaches us, and it is exactly similar to the propagation of light.

9. It turns out that the strength of a magnetic field is proportional to the amount of current.

10. Liquids, except for liquid metals, are poor conductors of heat, but it does not mean, however, that they are incapable of conducting heat.

B. 1. It is an accelerator that accelerates elementary particles of matter and imparts to them enormous energy.

2. It was Rutherford who first proposed a general theory of radioactive transformation.

3. It is in a transmission line that one should use as good a conductor as possible.

4. It is the flow of current in the conductor of that device which produces a magnetic effect.

5. It was Mendeleev who had spent twenty years studying the chemical elements.

6. It is hydrogen, one of the elements composing water, that attracts the attention of scientists.

7. It was not until the middle of the 19^th century that the molecular-kinetic theory of gases found its further development.

8. It was not until October 4, 1957 that the world's first man-made satellite was launched.

9. It was not until 1765 that the first steam engine for industrial purposes was constructed by Polzunov.

10. It was not until 1930 that the first analog computer was built.

11. It was in 1820 that the first real calculating machine appeared.

One

Числительное	Неопределенно-личное местоимение	Слово-заменитель упомянутого существительного
Many substances exist only in one state. Многие вещества существуют только в одном состоянии.	One has to be careful while testing ventilators for conditioning rooms. Нужно быть внимательным при испытании вентиляторов, кондиционирующих помещения.	Some materials are good conductors of heat and others are poor ones. Некоторые материалы – хорошие проводники тепла, а другие плохие.