TASK 2. Fill in each numbered blank with one suitable word or phrase.

More than a billion people all over the world are (1) _______the threat of desert expansion, but few of them are aware that they themselves cause it and are also its victims. People cut down trees for fuel and farmland. Their herd eat up the grass covering valley floors and hillsides. The climate and soil quality, therefore, are affected and forests are turned into (2) _______.

In some places, many people had to leave their homes when their wells became dry and sand buried their houses and crops. Therefore, thegovernment in nearby areas hashad local people (3) _______trees and banned burning firewood for fuel. Many techniques have been used. For example, in Iran, a thin covering of oil was poured on sandy areas to retain (4) _______for planting trees, but this method may harm the environment. Other countries built long canals or pipelines to carry water to desert areas. Unless people find more (5) _______methods, their homes and land will be lost. The fightagainst the desert is continuing.

The teacher told us that Columbus ________ America in 1492. A. discovered B. had discovered C. was discovering D. would discover