Контрольная работа по английскому языку № 4

для студентов I курса очно-заочного факультета ЛГТУ

всех технических специальностей

Вариант 2

ABOUT METALS

Man has used metals for centuries in gradually increasing quantities, but it was not until the Industrial Revolution that they came to be employed in really vast quantities.

Today we know more than sixty-five metals, the majority of which are available in large enough quantities to be used in industry. With the increase in the number of metals has come an increase in the number of their alloys. How many alloys there are in the world is difficult to estimate, because their number increases daily, but a moderate estimate gives it as five thousand.

The discovery of steel alloys brought a high demand for certain metals such as tungsten, chromium and vanadium, which previously had been in very moderate use. On the other hand, we have metals that possess valuable properties but which are extremely limited in use because of their rarity in the earth's crust or the difficulty of their production.

Tungsten is a metal of which the importance as a material has only recently been appreciated. Tungsten in small quantities makes the steel so hard that it can cut even when made white hot by friction. It is the secret of the machine tools which you can see at work in every factory where metal is cut.

Because of its high melting point (it is but twice lower than the temperature of the surface of the sun) it is widely used for the filaments of electric lamps and valves.

Another metal with a great future is tantalum, which combines a number of remarkable properties. Some of them are resistant to acids, have a very high melting-point, considerable strength and unusual electric properties.

Platinum is one of the most useful metals and, if it were available in larger quantities, would be widely used for many purposes. It resists to acids; and it can be drawn into wire 1/50,000th of an inch thick, invisible to the naked eye.

In various fields, the metallurgist provides new materials for every need. It must not be supposed that the "old" metals are falling out of use. Far from it, for copper, tin, silver, zinc, and nickel are being more widely used, both in the comparatively pure state and as alloys. Silver, for centuries regarded only as a kind of wealth, has become of major importance for photography.

The age of electricity has greatly increased the demand for copper, one of the best conductors. Alloys of beryllium and copper can be made as hard as steel. Used for springs or switches, they have an almost unlimited life.

This is but a brief survey of some of the metallic substances that science has made available to man. Research results in new materials being discovered, and the "nearly perfect" of yesterday becomes the "not quite good enough" of today. There is little doubt that progress will be still more rapid during the next century. Research is likely to give us alloys in the near future that will entirely substitute for every one of our most modern metallurgical discoveries.

I.Прочитайте текст и переведите его на русский язык письменно.

II. Заполните пропуски в предложениях, используя текст, и переведите пропущенные слова на русский язык.

1) Today we know more than 65 metals, . . . of which are available in large enough quantities to be used in industry. 2) On . . . , we have metals that possess valuable properties but which are extremely . . . in use because of their . . . in the . . . or the difficulty of their production. 3) Tungsten in small . . . makes steel so hard that it can cut even when made white hot by . . . . 4) Another metal with great future is . . . , which combines a number of . . . . 5) Alloys of beryllium and copper can be made . . . . . . . 6) Used for . . . or . . . , they have an almost unlimited life.

III.Найдите в тексте и выпишите предложения с глаголом в Present Perfect Active. Переведите предложения письменно.

Образец: I have just done it.

Я только что сделал это.

IV.Раскрывая скобки, напишете каждое предложение три раза, построив условные предложения I, II и III типов.

Образец: If you (to be) free, I (to come) to see you.

If you are free, I will come to see you.

If you were free, I would come to see you.

If you had been free, I would have come to see you.

1) If I (to live) in Moscow, I (to visit) the Tretyakov Gallery every year. 2) If she (to know) English, she (to try) to enter the university. 3) If my friend (to come) to see me, I (to be) very glad. 4) If my mother (to buy) a cake, we (to have) a very nice tea party. 5) They (to be surprised) if I (to make) such a mistake.

V.Раскройте скобки, употребляя глаголы в требуемой форме.

1) If she (to ask) me yesterday, I would certainly have told her all about it. 2) If you (to do) your morning exercises every day, your health would be much better. 3) If he is not very busy, he (to agree) to go to the museum with us. 4) If I (not to be) present at the lesson, I should not have understood this difficult rule. 5) If he reads fifty pages every day, his vocabulary (to increase) greatly.

VI.Переведите следующие предложения на английский язык.

1) Если бы я узнала об этом раньше, то не сидела бы сейчас дома. 2) Она здорова. Если бы она была больна, её брат сказал бы мне об этом вчера. 3) Вы бы много знали, если бы регулярно читали этот журнал. 4) Если бы он не следовал советам врача, он бы не поправился так быстро.