根据提供的信息和语言素材设计教学方案，用英文作答。

设计任务：请根据以下教学内容设计一节听力课的教案。该教案应突出以下要点：

    Teaching objectives

    Teaching key and difficult points

    Major steps and time allocation

    Activities and justification

    教学时间：45分钟

    语言素材：

                                                                               FIGHTING GROWING DESERTS

 Why do we have deserts today? Deserts have not always been here. Most deserts that we have today were once green lands full of the plant life. One of today's biggest deserts is in North Africa.However,in the lst century BC farms in the North Africa grew corn and wheat to make bread for the whole city of Rome. How did this area become desert?Both weather and people can help forma desert. Hot weather or very little rain makes the land so dry that nothing can grow.lf people cut down or burn trees and plants to make land clear for farming,the wind can blow the soil away and tum the dry land into sand. Another big problem is farming on land that is not very good.This poor land can very quickly turn into desert,if it is farmed too much. One of the biggest causes,however,is when people take their animals to the same fields to feed over and over,and the fields finally lose all their nutrition. Because of these problems,deserts are slowly taking over green land in many parts ofthe world,including China. However,we can fight the growing deserts!  In some parts of China people are working to prevent desert from expanding. In Xinjiang, for example, some farmers are trying new scientiric farming methods.These methods make it possible to use less land for crops,so farmers then can plant trees on the rest of their land!One Xinjiang farmer,used only half of his fields to grow the same amount of crops as last year. On the other half of his land,he planted fruit trees. The work of people like this is helping tofight the world's growing deserts.