初三英语上学期lesson 42

,50,100,0,1620,1850,50%,33%,THE UNITED STATES OF AMERICA,Look at the diagram. It shows us what has happened to the forests of the USA in the last 350 years. In 1620, about half the USA was covered by forests. In 1850, abut a third was covered by forests. Today, the forests have almost gone. A lot of good land has gone with them, leaving only sand. Today, too many trees are sill being cut down in the USA.,16年后，大兴安岭将无木可伐。,The flood of Changjiang River in 1998,Questions,1） Have you ever heard of the Great Green Wall?2) What do you know about the Great Green Wall,THE GREAT GREEN WALL,China has built a new Great Green Wall, “ Sanbei shelter-forest” across the northern part, including Inner Mongolia, Shannxi, Hebei, Beijing,and Tianjin. The Great Green Wall also covers some of the Northwest(Xinjiang, Qinghai, Gansu, Ningxia and Shaanxi) and the western part of the Northwest( Liaoning, Jilin and Heilongjiang). It includes altogether 13 provinces, cities and autonomous regions. Its total area is 4,069,000 square kilometers, which covers 42.4% of the land of China. The building of the Great Green Wall will take 73 years (19782050). The Great Green Wall has already saved a lot of land. They are millions of trees, theyre forests.,The functions（作用） of trees,1. Clean air .,2. Give us wood .,3. Produce oxygen ( 氧气).,4. Keep us cool in summer.,5. Hold soil and water,6. Stop lands from becoming deserts.,7.Offer birds and some animals homes .,8. Make our world more beautiful.,What can forests do?,1.They help to keep water from running away. 2.Keep rain drops from hitting the soil directly. 3.The dead leaves on the ground keep the water from running away. In this way,floods and droughts can be stopped.,DO TRUE OR FALSE STATEMENT,1.The Great Green Wall is just the Great Wall.,( F ),2.China builds it across the southern part of China.,( F ),3.It can keep water from running away. It can save a lot of good land.,( T ),the importance of forests.,Forests help to keep floods and droughts from happening.,Para.23:,Para. 1:,Something about the Great Green Wall,Main idea:,Topic sentence: Chinese people do not want to see more floods and droughts . So they have built a new Great Wall of trees across the northern part of the country.,Main idea:,Topic sentence:,Para.46:,Main idea:,Something about Wang Feng , other workers and their work. What Wang Feng thinks about the Great Green Wall and his work.,THE GREAT GREEN WALL,Special features(特征),Functions （功能）,Wang Feng andother workers,Across the northern part of China7000 kilometers long Between 400 and 1700 km wide,It stops the wind from blowing the earth away and stops the sand from moving towards the rich farmland in the southIt has saved a lot of good land.,They work at Yulin in Shanxi.They have planted ten thousand trees this year. Its difficult to work on the Great Green Wall.They have to grow their food.,Retell the story with key words,Interview,ws