4. Finish the following sentences according to the text.

1) The processes of moisture transfer from the sea to the land and back to the sea again are known as…

2) Vapour condenses into visible water droplets which form …

3) The hydrologist must be interested only in … precipitation.

4) More than half of the precipitation which reaches the surface of the earth is returned to the atmosphere by the combined process - … .

5) People tap … for their own uses.

6) Water is diverted temporarily from one part of the cycle by … .

7) Water resources engineer is involved in … .

8) Scientists and engineers in hydrology may be involved in both … .

9) The work of hydrologists may range from … .

5. Answer the following questions.

1) What is hydrology?

2) Does hydrology deal with the chemical and physical properties of water in all its phases?

3) The world's supply of fresh water is obtained almost entirely as precipitation resulting from evaporation of sea water, isn’t it?

4) What is hydrologic cycle?

5) What is the first stage in the hydrologic cycle?

6) What starts the hydrologic cycle in motion?

7) What carries the vapour over the continents?

8) What happens when the vapour is cooled to its dew point?

9) Are all precipitations returned to the atmosphere by evaporation from water surfaces, soil and vegetation and through transpiration by plants?

10) What does precipitation include?

11) Precipitation occurs in various forms. What are they?

12) Why do people have to use dams to supply some cities with water throughout the year?

13) What is evaporation and transpiration?

14) What is water used for?

15) How is water diverted from the hydrological cycle?

16) Why do downstream users often pose a problem of water quality?

17) What problems do hydrologists have to solve?

18) What do hydrologists involved in field investigation (office work) do?

6. Read the text again, make a plan of it and write a short summary of the text.

7. Match the meanings of the terms with their definitions.

a) precipitation	c) vapour	e) moisture
b) evaporation	d) transpiration

1. It takes place when plants give off moisture through their leaves.

2. A liquid such as water in the form of very small drops, either in the air, or on a surface, esp. a cold one.

3. It occurs when moist air cools and water vapour condenses on tiny particles in the air, such as dust or salt. The water particles then collect together, and may fall as snow, rain, sleet, etc.

4. It occurs when liquid water changes into water vapour as a result of heating. Water vapour is invisible.

5. Gas which results from the heating of a liquid or solid.

8. Match the words with their synonyms.

1) start	a) discharge
2) hydrologic cycle	b) increase
3) tiny	c) begin
4) extend	d) subsurface water
5) groundwater	e) water cycle
6) accumulate	f) involve
7) place	g) collect
8) include	h) location
9) over	i) small
10) release	j) above