阅读理解 From the beginning rivers have played an important part in the life of man. Primitive man used rivers as a means of travel.
In ancient times, man settled near rivers or on river banks and built up large empires and civilizations. The Menam runs through modern Bangkok(曼谷), still serving as a great water-way for the transport of goods and people.
Water is nature's most precious gift to man. Man needs water to irrigate his crops, to cook and to wash. In nations far and wide rivers mean life and wealth. The Irrawaddy, Nile, Ganges and a host of others feed and clothe the nations around them. A shortage of water in heavily populated agricultural areas will cause great hardship and starvation as crops fail.
Water is also a source of energy and power. Man constructs huge dams across rivers to control the water irrigation and obtain the energy needed to drive generators. The electrical power is then channeled to homes, cities, factories, television stations and the military(军方).
Man uses billions of litres of water each day. His main source of water comes from reservoirs which in turn obtain their water from the rivers.