DESERTSI. PRONUNCIATIONCHOOSE THE WORD WHOSEUNDERLINE PART IS PRONOUNC...

45. According to the passage, which of the following is the most important cause of desertification? A. The change of climate B. The spread of deserts C. Human activities D. Cattle destroying trees V. Choose the word or phrase (A, B, C, or D) that best fits each space in the following passage. Desertification The Sahara Desert is growing by 10km each year. The whole earth gets 600km2 of desert area more every year. This process is called "desertification." This term started being (46)__________in the 1950s. The idea of desertification was first known in the 1930s. Much of the Great Plains grew very dry (47)______________a result of drought and poor farming techniques. It was called the "Dust Bowl." Millions were forced to leave their farms and their ways of life. Since then, (48)______________have been great improvements in farming practices in the Great Plains. These have prevented the "Dust Bowl" disaster (49)________again. Grazing is one worry. Cows do two things to the soil. First, they eat grasses and plants that hold the soil in place. Second, their hooves break down the top layer of soil. The result is that the good soil can be blown away by the wind. The dirt (50)___________behind is not good for growing.