Lexical Exercises. Exercise 1.Find the English equivalents for the words and word-combinations
Exercise 1. Find the English equivalents for the words and word-combinations given below. Use them in the sentences of your own. огромный запас золота; засесть за работу; рассматривать; имитация золота; известный метод; драгоценные металлы; высокая точка плавления; химическая промышленность; ювелирное украшение; измерять; терять блеск (окисляться); серебро высшей пробы; фотопленка; серебряные копи.
Exercise 2. Match the English words and word-combinations given below with their Russian equivalents. 1. to critisize for 1. в поисках новых земель и богатства 2. remarkable achievements 2. повысить износостойкость 3. seeking more land and wealth 3. богатый драгоценными металлами 4. to set to work 4. растянуть в проволоку 5. to equal smth 5. отражать свет 6. to increase durability 6. засесть зa работу 7. to reflect light 7. быть равным ч-л 8. rich in precious metals 8. наименее химически активный металл 9. the least chemically active metal 9. удивительные достижения 10. to draw into a wire 10. критиковать за
Exercise 3. Answer the following questions: 1. What are the precious metals valued for? 2. When did the Spanish expeditions set fot South America? 3. What did they find there? 4. What was their most exciting discovery? 5. Why is it easy to hammer gold into thin sheets? 6. Where is gold used? 7. What are the properties of silver?
Exercise 4. In the text given above you could find the fragments of the definitions of gold and silver. Make them complete definitions. Listed in the box are some guidelines for writing good definitions. They are followed by poorly written definitions. Say, what is wrong with them and correct them.
1. Identify the class. You may also use descriptions, comparions, examples. 2. Be precise. Do not only identify the class, but give the characteristics that differentiate this object or phenomenon from others. 3. Use negative definitions (like “An apple is not a vegetable”) when you think people have a wrong idea. But then follow it with a proper definition. 4. Be objective. Always remember about those you are speaking to. A child needs an easier and more detailed definition. 1. An apple is round, red and about the size of a fist. 2. An astronomer is a scientist. 3. Radium is an element. 4. A pizza is something really good to eat. 5. Helium is light. 6. Barometer measures air pressure. 7. Conduction transfers heat. 8. An agronomist is a person who practises agronomy.
Exercise 5. Translate at sight. Metals and Non-metals The 105 elements do not, fortunately, exhibit 105 completely different sets of properties. When the major properties are considered it is found that the elements fall into one or two groups, the metals or the non-metals. The contrast between the properties of these two groups is given below. It is not to be expected that all elements in one class will agree in every detail; some differ in one or two properties from the others of their class; these exceptions are indicated in brackets. Metals Non-Metals Physical properties 1.Solid at room temperature (mercury 1.Many are liquids and gases at room is the only liquid metal) temperature 2.Have a high density (except 2. Density is usually low potassium and sodium) 3.Can be moulded by pressure, i.e. 3. Solid non-metals are brittle they are malleable 4.Have high melting points and 4. Have low melting points and boiling points boiling points 5.Are good conductors of heat, 5. Are poor conductors of heat and electricity electricity (graphite is the only good conductor of electricity among non- metals 6.Can be drawn into wire, i.e. they 6.Cannot be drawn into a wire are ductile Chemical properties 7. Have basic oxides 7. Have acidic oxides 8. React with dilute acids form- 8. Salts of non-metals do not exist ing salts 9.Form positive ions 9. Form negative ions 10.Are liberated at the cathode 10. Are liberated at the anode during electrolysis (hydrogen during electrolysis acts as a metal) The chemical properties are much more conclusive than the physical properties for deciding whether a particular element is to be regarded as a metal or a non-metal, e.g. if an element forms a basic oxide it must be classified as a metal. A basic oxide is never formed by a non-metal.
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