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1) :

 

To transmit the image by radio has become a practical possibility not so long ago.

 

- :

 

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, , , it, :

 

It is difficult to liberate an active element from a compound. .

 

: to say , to see - , to hear , to state , to report , to announce , to believe , , to suppose , to think , to expect , , to know , to understand , to consider , to assume , to declare .:

 

Uranium is known to possess the highest atomic weight. , .

 

Uranium, , .. :

 

Uranium to possess the highest atomic weight ( , ).

 

(is known + to possess).

- (, , , ..), , , .

, , :

 

Oxygen is known to be colorless. , .

 

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, to seem, to appear , to prove : is likely , ; is unlikely , , .

to seem, to appear, to prove . -, to prove :

 

The substance seems to have high melting point. -, .

 

The percentage of the carbon dioxide proved to be low. .

 

is likely is unlikely , , :

 

The reaction is likely to be violent. , , .

The reaction is unlikely to be violent. .

 

2) :

 

The purpose of this catalyst is to accelerate the process of chemical reaction.

 

:

 

, .

 

3) :

 

( to ):

 

All the progressive peoples must fight for peace. .

 

to be to have, to :

 

The voltage is to be measured. .

 

He had to start the experiment at noon. .

 

- :

 

Hydrogen is difficult to liberate from this compound. .

, , : to want , to like , , to intend , to hope , to promise , to begin .:

 

We hoped to obtain good results. .

 

to be going, to be about

 

to be going , , :

 

We are going to build the largest atomic pile in the world. .

 

to be about , , , :

 

He was about to start, but the engine suddenly stopped. , .

 

.

 

4) :

 

, , , :

 

He asked us to return. .

 

, for. , , for .

, :

 

We expected for the impurities to fall out as a precipitate. , . .

: for + Infinitive , .:

 

It is easy for you to do it. ( ).

It is not for us to decide. ( ).

 

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We expect him to come. , .

 

, him, to come, .. : him to come ( , ). , , , , , , , , , .

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) : to want , to wish , to like , to desire ;

) : to suppose , to consider , to think , to expect , to know , to find , ;

) : to order , to command , to allow ;

) : to see , to hear , to feel , to watch , to notice , to observe .

to :

 

We noticed the mixture change its color. , .

 

5 ) :

- ( ) . .

 

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Automation is one of the ways to increase productivity. .

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The wire to connect the terminals is 10 meters long. , , 10 .

 

( ):

 

The aperture to show the readings is on the left side of the apparatus. .

 

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Voltage, resistance, and capacity are the three important properties to influence the flow of current in a circuit. , , .

 

- , .

. :

 

The question to be discussed (which is to be discussed) is of great importance. , , .

 

: the first, the last.

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K. Tsiolkovksy was the first to prophesy the wonderful prospects of jet propulsion. . .

 

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( in order to):

 

The substance was placed in a cooling mixture (in order) to reduce its temperature. , .

 

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To reduce the temperature of the substance, it was placed in cooling mixture. - , , .

 

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, - :

 

To work well is the necessary condition of fulfilling the plan. .

 

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To work well he has read many books on electroengineering. , .

 

( : too, enough):

 

The transmitter is too weak to cover this distance. , .

 

too enough, :

 

One atom of oxygen combines with two atoms of hydrogen to form water. , .

 

I. :

 

 

1. To assign a numerical value to the inertia of any given body, we choose as a standard some body whose inertia is arbitrary taken as unity. 2. Each organ of the living organism has its own work to do. 3. When cells which have similar functions become congregated together to form distinct anatomical structures, we call such structures organs. 4. Oxygen is extremely hard to liberate from a compound. 5. The disintegration of radioactive substances is known to be a spontaneous process. 6. We know the electric cell to consist of two plates of conducting material assembled together and immersed in an electrolyte. 7. Atomic energy is likely to become the main source of power-supply in the years to come. 8. Dilute solutions appear to obey laws exactly analogous to the laws of gases. 9. The difficulties to overcome in the manufacture of synthetic camphor seem to be great. 10. There was a time when lightning proved to be a dangerous problem to be solved. 11. Devices for changing a.c. into d.c. are needed to charge storage batteries. 12. The weather is unlikely to change for the better in the coming days. 13. I asked him to inform me about the results of the test.

 

B

 

1. If the field winding is in series with the armature, all of the current to be generated must pass though it. 2. With a small current there must be a greater number of turns of wire on the field magnets to produce a magnetic field of adequate strength. 3. Water to make up for evaporation and to aid in digestion is a most necessary part of our food. 4. Many substances unite with water to give compounds which are called hydrates. 5. An active element is very difficult to liberate from a compound. 6. A video-amplifier is expected to cover a very wide range of frequencies. 7. Temperature changes up to 200 C appear to have no effect on this substance. 8. The study of electricity seems to have begun about 1600 when the first book on experiments in electricity appeared. 9. We know the sun to be intensely hot. 10. It is unlikely for the oxygen to be easily liberated from this substance under such a temperature. 11. We know the storage batteries to contain chemicals generating electric current under certain conditions.

 

C

 

1. The Chinese appear to have been the first to use pieces of lodestones as compasses. 2. When two elementary substances combine, the process involves the union of the two kinds of atoms to form compound molecules. 3. The radio signal is too weak to be detected at this distance. 4. When the wire is connected in such a manner that the current can flow through it, the circuit is said to be closed. 5. We know all bodies to consist of atoms. 6. To tear away from the liquid the molecule which leaves it is to have a large amount of kinetic energy. 7. A non-ionized clean air is considered to be good insulator. 8. An important problem which is to be considered with regard to any engine is the question of its efficiency. 9. When iron and water are heated in a closed vessel, the hydrogen and the oxide of iron which are produced react with one another to give back water and iron. 10. The next step to be taken in this process involves the treatment of camphor with acetic acid. 11. This problem has to be solved as soon as possible. 12. Nakhirnov is known to have been one of the most talented Russian admirals. 13. Gallileo carried out a special experiment to prove that heavy objects fall not faster than light ones.

 

II. , :

 

GRAVITY

 

The force of gravity is known to play an important part in many common phenomena of mechanics, as well as in everyday life.

We know the weight of a body to be nothing but the pull of gravity toward the earth. A body is said to weigh one kilogram if the mass of the earth exerts upon it a pull equal to one kilogram.

According to the universal Law of Gravitation, any two objects in the Universe are attracted to each other with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between them.

The Law of Gravitation is universal, of course, but it is impossible to notice the force between two ordinary objects as the attraction between them is too small to be perceptible at all.

But with a body as large as the Earth or the Moon it becomes a different thing. It is this force that holds the planets in their circular orbits and due to this very force the first man-made earth satellite created by Soviet scientists began to circle around our Globe.

We know gravity to pull on every particle of a body so that its weight is actually distributed throughout the body. But a solid body seems to have one point at which it can be supported by a single upward force, this point is called the centre of gravity. In technique the centre of gravity is considered to be the location of the resultant of all gravitational pulls exerted on the body.

Now we are to consider the question of stability, interrelated with gravity.

A book lying on a table is expected to keep its position without any difficulty, as one knows it to be in a state of equilibrium. However, to make it stand on end is not so easy at all. In the same way, a pencil will lie on the table without any tendency to tip over. With some difficulty one can even make it stand on its unsharpened end, but it will not stand at all upon its sharp end.

All common objects differ in their tendency to keep a given position, their stability depending on their shape, weight, and position, and everyday experience shows us that heavy objects are harder to tip over than light ones. The stability of an object is measured by the amount of work to be required to make it take a new position. The lower the centre of gravity, the greater the stability of an object; that is why, to increase the stability of a motor-car, its designer tries to keep the centre of gravity as low as possible.

 





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