VIII. Translate the following sentences paying attention to the use of Perfect Tenses:

1. By the end of the previous term the students had mas­tered the necessary lab techniques. 2. By the end of the year they will have settled all the problems and will begin their tests. 3. They have developed the new waterproof cable which will help to solve all the problems relating to telephone service failures since water cannot enter the space between insu­lated conductors. 4. He has already returned to Moscow. 5. I have known him since 1980. 6. I have never been to Kiev.7. Have you ever been to Kiev? 8. The scientists of our lab­oratory had been carrying out experiments with a new type of insulating material for several years before they got positive results. 9. Our engineers had been testing the new device for some months before it was put into service. 10. By the end of the year they will have been carrying out field trials with a new teleprinter for several months. 11. They will have been carrying out this work until they get the necessary data.

IX. Translate the following sentences paying attention to the functions of "it":

1. It is not the sound of the voice that travels over the wire when we talk over a telephone. 2. If the valve in the cylinder moves easily, it should be replaced immediately. 3. When a ray of any kind strikes an atom, it may knock an electron out of the atom. 4. It is to be noted that ocean cables are one of the most dependable means of transmission yet designed. 5. It is impossible to increase the number of telephone channels on open-wire lines without applying car­rier equipment. 6. It was in 1957 that the first man-made satellite was launched in our country, and now man has already set his foot on the Moon, sends probes to distant planets and orbits the Earth in space vehicles. 7. It was found that a needle of a compass moved when it was put near a wire with a current flowing through it. 8. It was exciting to be able to communicate over long distances by signals sent by wireless. 9. It seems unlikely that this experiment will give good results.

X. Translate the following sentences paying attention to the func­tions of "that":

1. The fact is that our era began with the discovery of the electric current. 2. The mixture is identical with that mentioned above. 3. Most frequently the force is resolved in such a way so that the components could be at right angles to each other. 4. Energy that is produced by hydroelectric stations is used for industry, agriculture and other needs of our national economy. 5. The transmission of information by radio waves requires that some specific installations be em­ployed. 6. That this system has far-reaching possibilities and proves to be of great value to business executives, engineers and scientists is known to everybody.

XI. Translate the following words paying attention to the suffixes;

operator, buyer, difference, efficiency, importance, free­dom, transmission, combination, development, strength, changeable, different, unsuccessful, useless, famous, sim­plify, characterize, memorize, frequently