Text d The Earth

Task. Scan the text. Choose the one best alternative to each question following it. Answer all the questions on the basis of what is stated or implied in the text.

To primitive man the earth was a flat disc with its surface diversified by mountains, rivers and seas. It was Aristotle who used arguments showing that the earth is spherical. These arguments are: 1) a ship which is sailing away from the shore is disappearing gradually, hull first, masts later 2) during an eclipse the earth casts a circular shadow on the moon and it is a spherical body that casts a circular shadow on the moon 3) when one is passing from place to place on the surface of the earth the appearance of heaven is constantly changing. But men believed that the earth is a sphere only after the explorers sailed around the earth (circumnavigated it).

Actually the earth is not a perfect sphere but a spheroid flattened near the poles. The circumference of the earth at the equator is about 25.000 miles.

The earth rotates about its polar axis and at the same time is revolving around the sun. The sun in its turn is not fixed in space but shares in the general motion of the solar system relative to the stars.

The geological evidence shows that most of the land surface is covered with a layer of sedimentary rocks, such as sandstones and shales. In addition large areas within the continents are covered with ancient rocks like granite. Geologists believe there is a widespread granitic layer under all the continents.

Below the ocean the structure is different. There is no granitic layer and basalt comes right up to the ocean bottom.

When the earth formed it was very hot. As it was cooling an ocean was forming and rain and rivers, denudation and sedimentary rocks came into existence. The simplest method by which we can determine the age of the earth is based on denudation. If we know the total mass of sedimentary rocks over the earth's surface and the annual amount of sediments carried to the sea by rivers, a simple division shows that the age of the earth is between 1.500 and 3.000 million years.

From the Encyclopaedia Britannica.

Ex. 1. Which of the following does the text mainly discuss?

1. a recent development in astronomy

2. a recent exploring

3. the shape of the Earth

4. famous explorers

1. The word circumference is closest in meaning to

1. calculation

2. measurements

3. distance round

4. circle

1. What conclusion can be made about the simplest method of determining the age of the Earth?

1. it is based on denudation

2. it is based on arguments

3. it is based on a recent development

4. it is based on travellers’ data

1. The word circular is closest in meaning to

1. fast

2. round or curved in shape

3. perfect

4. complete

1. According to the text, what is circumference of the Earth at the equator?

1. 20.000 miles

2. 10.000 miles

3. 35.000 miles

4. 25.000 miles

1. Who used arguments showing that the earth is spherical?

1. Eratosthenes

2. Aristotle

3. Parmenides

4. Archimedes

1. According to the text, what kind of shadow does the Earth cast on the Moon during the eclipse?

1. circular

2. constant

3. long

4. round

1. Which of the following is true about the land surface?

1. it is covered with sedimentary rocks

2. it is covered with vapor

3. it is covered with narrow floor

4. it is covered with space bodies

8. What is there under all the continents?

1. basalt

2. sandstones

3. granitic layer

4. shales