3. 沙漠化 　　[2./图表描述段]As is shown in the picture, we can see clearly the relation ship between people and desert. In the left hand picture, people are fleeing from greedy sand hills because they cut down all the trees. The caption reads, As the sand advances, we retreat. In the right hand picture, the people have returned carrying tools, water, and young trees to plant the land again. The caption reads: As we advance, the sand retreats. 　　[5.意义阐述段]It seems to me that the cartoonist is sending a message about the importance of trees in water and soil conservation and the need for everyone to fight against the danger of the desertification. In fact, what he is saying is that the sand hills will drive away from the land if we do fight against the sand. If we let this situation continue as it is , our environment will suffer a great destruction. 　　[10.建议措施段]The best way to fight back against the greedy desert in made clear in the second picture. There the local people are actively setting about the task of planting trees to reclaim the land and make it fertile. The fact that there are three people in the picture, each with a different job suggests that working together is the key to success in the battle against soil erosion.