III. Copper. (Read and translate the text in a written form.)

Copper is easily worked and is remarkably ductile. It can be cold-rolled down to one one-thousandth inch in thickness, and, by cold drawing, its length can be increased as much as 5,000 times. Hence it is an ideal metal for making wire. It has pleasing colour and lustre, it takes a high polish, and it forms alloys readily with almost all metals .For cooking utensils, copper must be coated with tin to prevent the formation of harmful compounds.

About one half of the copper used, for example, in the United States is for electrical equipment. Another third is used in fashioning metal products such as pipe, tubing, and other plumbing fixtures, hardware, and machine tool products. Copper is used in the transportation industry, refrigeration equipment, and other miscellaneous uses accounts for the remainder.

IV. Chromium. (Read and retell the text in English.)

A silvery white metal, chromium was discovered by a French chemist in 1797, but it remained largely a laboratory curiosity for more than a century. The long delay in its gaining widespread use was due to its high resistance to heat and chemicals. Extracting it from ores by methods formerly used was costly and difficult. But this same unyielding character has made chromium commercially important today.

Because of its toughness and resistance to chemical action, as little as 10 percent of it mixed with iron or steel protects these from corrosion, producing the “stainless and rustless” alloys out of which thousands of articles are now made, from kitchen knives and surgeons' instruments to automobile trim. Chromium plating has largely replaced nickel plating because of its superior hardness and resistance to chemical action. Heat-resisting chromium alloys are employed for high-temperature chemical apparatus, and the chief chromium ore, chromite, is used to make bricks for lining furnaces.

V. Iron and Steel Industry. (Read and retell the text in Russian.)

Modern life depends greatly on iron, the most widely used of all metals. It is needed to carry out even the simplest daily tasks. Iron, usually in the form of steel, is nearly always helping to do the job. The concrete in highways and in towering buildings needs steel for added strength. Transportation relies on the metal, whether in the form of an iron horseshoe or as a special steel alloy in a vehicle sent into outer space. A complete list of all the uses for iron and steel would seem endless, and new uses are found each year.

Since the beginning of the Iron Age, about 1000 BC, human progress, in peace and war, has been greatly dependent on equipment made with iron. First came tools of metal to fashion many of the other needed goods. Eventually this was followed by the Industrial Revolution and the mechanization of farms. Machine tools and other equipment made of iron and steel changed the economy of both city and farm.

VI. Lead. (Read the text and make its summary in English.)

Few metals have been used in more different ways than lead. Lead ornaments and coins have been in use since ancient times. The Romans used lead for water pipes and for solder. In the Middle Ages strips of lead called cames were first used to assemble the pieces in stained-glass windows.

In the United States about two thirds of all the lead produced is used in electric storage batteries of the kind found in automobiles and large amounts of lead are used as protective coverings for electrical cables, and there are lead compounds in paints and pigments. The use of lead in paints has been decreasing because lead is poisonous, and many children have been poisoned by eating flakes of dried paint containing lead. Lead bullets and shot made gunpowder effective in firearms. Lead is the main ingredient of solder, used for joining pieces of metal.

Lead is the heaviest and the softest of the common metals. Because it resists attack by air and water as well as by many strong chemicals, it can be used to protect electrical cables, or to line large vessels in which chemical processes are carried out. Screens to protect people from X rays, gamma rays, and radioactive materials are made from lead because it absorbs radiation. For this reason lead is used as a protective shield around nuclear reactors and particle accelerators.