4 С. Dialogues

Memorize these dialogues and perform them in pairs.

I. - What do you know about cement?

- It's a powder which, when mixed with water, becomes hard like stone.

- Suppose we mix cement with sand and stones?

- If we mix cement with sand and stones, we get concrete.

II - Do you know what a brick is?

- Yes, I do. It is a block of baked clay.

- What are bricks chiefly used for?

- They are chiefly used for building houses.

III.-What kind of a building is called a "skyscraper"?

- A skyscraper is a very, very tall building.

- How tall are some skyscrapers?

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10. Are the uses of aluminium almost illimitable? 11. How many building products are now made of aluminium? 12. Was there a time when aluminium was as valuable as silver?

5C. Dialogues

II. Read the dialogues and use the conversations in pairs.

Dialogue 1.

A: What can you say about aluminium as a structural material?

В.: You see, aluminium has many attractions as a structural material.

A.: Can it be readily obtained in various alloys?

В.: Yes, it can be readily obtained in various alloys.

A.: And can it be obtained in various conditions and shapes?

В.: It can - to suit specific uses.

A.: You haven't said anything about aluminium's reliability.

В.: Oh, there is sufficient experience now to have confidence in its reliability.

Dialogue2

A.: Aluminium alloys of very high strength are obtainable, aren't they?

В.: They are, but such alloys are not generally used in structural engineering.

A.: Is corrosion from sea air or industrial pollution a problem?

В.: No, corrosion from sea air or industrial pollution is no longer a problem.

A.: So that means that painting is not necessary?

В.: You are right. Painting is not necessary at all.

Dialogue 3

A.: I've heard that aluminium lends itself particularly well to

roofing. Is that so?

В.: Yes, that's so. Aluminium is a wonderful roofing material!

A.: But it must be very expensive. Don't you think so?

В.: It is rather expensive, but there are many instances were aluminium structures justify themselves. – 25 -

for energy conservation. 4. In direct contact with a heat source, aluminium is an excellent conductor. 5. World's lightweight champion in the long-distance transport of electricity, aluminium has virtually replaced heavier copper in high-voltage power lines. 6. Nearly indestructible aluminium can be remelted over and over. 7. Aluminium is alloyed with small amounts of other metals. 8. Copper adds strength; magnesium imparts additional marine-corrosion resistance. 9. Unlike copper or iron, aluminium does not occur naturally in metallic form. 10. Aluminium exists only in combination with other elements, primarily oxygen, with which it forms an extremely hard oxide known as alumina. When tinted by traces of other elements, alumina can take the form of gems such as rubies and sapphires. 11. Constituting 8 per cent of the earth's crust, aluminium is the most abundant of metals, as well as one of the hardest to produce. 12. Even fly ash from coalbuming furnaces could become a source of aluminium. 13. Subduing the waves, aluminium alloys not only combine lightness with strength but stoutly resist salt water's corroding effect. 14. When we recycle aluminium, we save 95 per cent of the energy needed to make new metal from bauxite. IS. Once you make aluminium it becomes an energy bank that you can tap over and over again. 16. The uses of aluminium are almost illimitable. 17. Aluminium panels sheathe the World Trade Center in New York. 18. Builders can use aluminium nails, and bolts to install aluminium storm doors, screens, flashing, gutters, downspouts, shingles, awnings, and Venetian blinds - some 200 building products in all. 19. In 1884, when aluminium was still as valuable as silver, a hundred-ounce tip of the metal was chosen by architects to finish the 555 ft high Washington Monument in Washington, D. C, USA.

II. Answer these questions:

1. Can aluminium alloys possess the strength of steel? 2. Is aluminium an excellent conductor when it is in direct contact with a heat source? 3. Has aluminium replaced copper- in high-voltage power lines? 4. Do you think aluminium can be remelted over and over? 5. Does copper add strength when it is alloyed wi th aluminium? 6. Is it true that aluminium exists only in combination with other elements? 7. When combined with oxygen, what does aluminium form? 8. Aluminium is not the most abundant of metals, is it? 9. Do aluminium alloys resist salt water's corroding effect?

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- Some are so tall that their tops are hidden by clouds when it rains.

IV.- Suppose you wanted to make some concrete, what would you take?

- I'd take some cement, gravel and sand. Then I'd mix them with water.

- Quite right! Now, what is concrete used for? • It's used for building, making roads, etc.

V-What is a lift?

- It's an apparatus for taking people up or down to another floor.

- Do the Americans call this apparatus a lift?

- No, they don't. They call it an elevator.

VI.- How long does it take to build such a house?

- It takes about ten or eleven months.

- How long did it take to build the house you live in?

-I suppose it took about a year and a half.

VI.- What do we call a number of rooms on one floor of a building?

- If the rooms are used as a home, then we call the rooms a flat.

- And what is an apartment?

- In England they use the word "flat", while in America they use the word "apartment".