V. Use the word in brackets to form a word that fits in the space.

1. The velocity of a stream . . . . increases in a downstream direction. (general)

2. Boulders in the stream bed increase turbulence and . . . . (resist)

3. Gradient is the . . . . of a stream. (steep)

4. Rapidly . . . . stream can carry cobbles. (flow)

5. In cold climate ice is an . . . . agent. (abrasion)

6. Capacity is . . . . to both current velocity and discharge. (proportion)

7. It depends . . . . on current velocity. (most)

8. During a flood, a stream overflows its banks and spreads over adjacent land . . . . a flood plain. (call)

9. The current lifts sand and carries it a short distance before . . . . it back to the bed. (drop)

10. The movement of a glacier resembles that of a river: the center . . . . more . . . . than the margins. (movement; rapid)

VI. Choose sentences in which the –ing form is a Gerund.

1. Creating great friction is common for a rough channel rather that for a smooth one.

2. Friction between flowing water and the stream channel slows current velocity.

3. Downward erosion is called downcutting.

4. For most streams, the lowest possible level of downcutting is sea level, which is called the ultimate base level.

5. A stream may cut through the rising bedrock to keep its original course.

6. Isolating the old meander from the stream produces an oxbow lake.

7. A meandering stream flows through the flood plain, forming a wide valley with a flat bottom.

8. If a stream cuts its way down to sea level, it would stop flowing.

VII. Translate the sentences.

1. Composition of granitic magma differs greatly form that of basaltic magma.

2. Scientists agree that the age of the Earth is approximately 4.6 billion years.

3. A braided stream is a stream that flows in many interconnecting channels.

4. Life originated during Archean time. That period is characterized by the evolution of first one-celled organisms.

5. Ural mountains are much older than those in Caucasus.

VIII. Make up questions beginning with the words in brackets.

Little erosion occurs in flooding streams during the remainder of the year. (Does?; When?; Where?)

IX. Read the text.

About 1.3 billion cubic kilometers of water exist at the Earth’s surface. If the surface were perfectly level, water would form a layer 2 kilometers thick surrounding the entire planet. Of this huge quantity, 97.5 percent is salty seawater, and another 1.8 percent is frozen into the great ice caps of Antarctica and Greenland. Only about 0.65 percent is fresh water in streams, underground reservoirs, lakes, and wetlands. Thus, although the hydrosphere contains a great amount of water, only a tiny fraction is fresh and liquid.

Are following statements true or false?

1. Water in streams, underground reservoirs, lakes and wetlands is salty.

2. Water forms a layer 2 kilometers thick surrounding the entire planet.

3. Hydrosphere includes waters in oceans, seas, lakes, rivers, streams and frozen in glaciers.