Tham khảo tài liệu 'english test 4 conservation', tài liệu phổ thông, ôn thi đh-cđ phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | English Test 4 -Conservation. Conservation is the safeguarding and preservation of 1 resources so that they can continued to be used and enjoyed. In the past most people believe that the world s resources could never be 2 up. Today we know that this is not true. An important part of conservation is the prevention of waste - waste of forests soil wild - life minerals and human lives. As important is the fight 3 pollution of our environment in particular the dirtying and poisoning of air and water. Conservation is also concerned 4 the reclaiming of land by irrigating deserts draining swamps or pushing back the sea. Farmers can protect their land by yearly rotation of crops - that is growing different crops 5 the same land from year to year. In this way different elements of the soil have time to replace lost elements. Farmers can help enrich the soil by adding fertilizers. They can prevent erosion by ploughing along the contours of a hill rather than up and down. In this way water does not run off and take the soil with it. Trees and shrubs are also needed to preserve land 6 their roots bind the soil and retain water. When all the trees in a region are cut the soil can easily become loose and blow away. Forests 7 timber one of man s most valuable resources but they must be managed carefully. Only mature trees should be cut leaving the young ones to grow bigger. To protect wild - life many countries have passed laws restricting hunting and fishing. Wild - life preserves areas where animals are protected 8 their natural environment are becoming more common in regions where animal life is threatened. Dirty air is chiefly a city problem. London s famous pea soup fogs were cleared by laws by forbidding the burning of soft fuels but car exhaust fumes continue to pollute the air. Some large cities may have to ban cars 9 the city centre to wipe out smoke. Minerals that are taken from the Earth in immense quantities include petroleum coal natural gas iron and copper. Once .
