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Nowadays, people are destroying rain forests of the earth seriously. It is (1)_______ that every year 100000 square kilometers of rain forests are (2)_______ for supply of wood paper and fuel as well as for the residence and (3)_______ land. Rain forests are very important for the world's climate. They receive the rainfall on the earth and produce a large amount of the world's oxygen. Destroying rain forests, (3)_____, is destroying our environment. Saving rain forest is an international problem. Nations need cooperation to (5)_____ rain forests, if not, it will be late.