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1. Образуйте форму множественного числа следующих существительных: element, nature, liquid, director, time,man, textbook.

2. Напишите формы возвратных местоимений, объясните правила их использования в предложении.

3. Образуйте степени сравнения следующих прилагательных и наречий: important, wild, interesting, little, bad,first, last, wonderful.

4.Прочтите и переведите тексты. Текст «А» переведите письменно и ответьте на вопросы после текста.



Text A. Steel

The most important metal in industry is iron and its alloy steel. Steel is an alloy of iron and carbon. It is strong but corrodes easily through rusting, although stainless and other special steels resist corrosion. The amount of carbon in steel influences its properties considerably. Steels of low carbon content (mild steels) are quite ductile and are used in the manufacture of sheet iron, wire and pipes. Medium-carbon steels containing from 0.2 to 0.4 per cent carbon are tougher and stronger are used as structural steels. Both mild and medium-carbon steels are suitable for forging and welding. High-carbonsteels contain from 0.4 to 1.5 per cent carbon, are hard and brittle and are used in cutting tools, surgical instruments, razor blades and springs. Tool steel, also called silver steel, contains about 1 per cent carbon and is strengthened and toughened by quenching and tempering.

The inclusion of other elements affects the properties of the steel. Manganese gives extra strength and toughness. Steel containing 4 per cent silicon is used for transformer cores or electromagnets because it has large grains acting like small magnets. The addition of chromium gives extra strength and corrosion resistance, so we can get rust-proof steels. Heating in the presence of carbon or nitrogen-rich materials is used to form a hard surface on steel (case-hardening). High-speed steels, which are ex­tremely important in machine-tools, contain chromium and tungsten plus smaller amounts of vanadium, molyb­denum and other metals.

Questions: What kinds of steel do you know? Where are they used?

Text B. Arabic Numerals

The Arabic system of numerical notation is used in most parts of the world today. This system was first developed in India in the 3rd century ВС. At that time the numerals 1, 4, and 6 were written in the same form as today.

The important innovation in the Arabic system was the use of positional notation, in which individual number symbols assume different values according to their position in the written numeral. Positional notation is made possible by the use of a symbol for zero. The symbol 0 makes it possible to differentiate between 11, 101, and 1,001 without the use of additional symbols, and all numbers can be expressed in terns of ten symbols, the numerals from 1 to 9 plus 0. Positional notation also greatly simplifies all forms of written numerical calculation.

Text C. Methods of steel heat treatment

Quenching is a heat treatment when metal at a high temperature is rapidly cooled by immersion in water or oil. Quenching makes steel harder and more brittle, with small grains structure.

Tempering is a heat treatment applied to steel and certain alloys. Hardened steel after quenching from a high temperature is too hard and brittle for many applications and is also brittle. Tempering, that is re-heating to an intermediate temperature and cooling slowly, reduces this hardness and brittleness. Tempering temperatures depend on the composition of the steel but are frequently between 100 and 650 °C. Higher temperatures usually give a softer, tougher product. The colour of the oxide film produced on the surface of the heated metal often serves as the indicator of its temperature.

Annealing is a heat treatment in which a material at high temperature is cooled slowly. After cooling the metal again becomes malleable and ductile (capable of being bent many times without cracking).

All these methods of steel heat treatment are used to obtain steel with certain mechanical properties for certain needs.

5. Переведите на русский язык следующие слова: annealing, quenching, tempering, intermediate, to immerse, indicator, treatment, ductile.

6. Переведите на  английский   язык  следующие слова и словосочетания: температура нормализации, мелкозернистая структура, охлаждение, состав стали, оксидная пленка, индикатор, закаленная сталь, промежуточный.

 7 . Переведите на русский язык предложение, содержащее модальный глагол или его эквивалент. If computers are ever to gain wide acceptance for process control they must be understood by the people who have to operate them.



8. Выпишите из текста «C» предложение, содержащее сказуемое в страдательном залоге. Переведите предложение на русский язык.

9.Составьте резюме, используя образец в Приложении.


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