IV. Complete the sentences

1. Sand is the result of ….

2. The fragments that are too hard or ….

3. … would be picked up by floods.

4. Many of the gravel pebbles were cracked and ….

5. If you look at sand under a magnifying glass, you will ….

6. … have either traveled a long distance.

7. … is composed of only one mineral.

8. If you pick up a handful of sand ….

9. … it may have interesting colors.

10. Some sand is so firm and hard packed that it ….

V. Agree or disagree with the following statements

1. Sand is a collection of gravel.

2. Each particle of sand may be from a tenth to a hundredth of an inch in diameter.

3. If you look at sand under a magnifying glass, you will not notice that there can be quite a collection of different particles.

4. Usually each grain of sand is composed of several mineral.

5. If there are iron compounds in the sand, it may have interesting colors.

VI. Write down all the properties that sand has

VII. Retell the text “sand”

***

I. Read and translate the text copper

Man discovered copper before any other metal except gold. Before the dawn of history, it was used by Stone Age men. Copper is found in a fairy pure stat, in lumps and grains of free metal. Probably men first picked up the lumps because they were pretty. Then they made the great discovery that these strange red stones could be beaten into any shape. This was an easier method of making weapons and knives than chipping away at flints.

Much later, other men discovered that they could melt the red stones and form the softened mass into cups and bowls. Then they started to mine for copper and to make all sorts of implements and utensils out of it.

For thousand of years, copper remained the only workable metal known, for gold was not only too scarce to be considered but also too soft to be practical. Copper tools were probably used in building the great Egyptian pyramids.

Few people ever see pure copper or would recognize it if they did. It is a shining, silvery substance delicately tinted with pink that turns a deeper red when exposed to the air. The copper we generally see has a dull reddish-brown surface. This is an oxide formed when he metal combines with the oxygen of the air. Most of the world’s copper exists in combination with other substances from which it must be separated before it can be used. Often it is found combined with sulphur in what we call a sulphide ore. This sulphide ore may be combined with such substances as iron and arsenic and this makes the separation of the copper difficult.

Copper has many other virtues besides that of outlasting most other metals. It is tough, yet soft enough to be pulled and pounded and twisted into any shape. It is an excellent conductor of heat as well as of electricity. It can be carved or etched, but is not easily broken. And it can be combined with other metals to make such alloys as bronze and brass.

Vocabulary

to discover - открывать

dawn - заря

lump - кусок

grain - зерно

to pick up - подбирать

pretty - красивый

discovery - открытие

to beat - бить

weapon - оружие

to chip away flint - откалывать

to melt - плавиться