Planting trees

　　 Answers: 1. be grown, is grown, be harvested, be harvested

　　2. be dug, have finished, dig, be finished

Exercises in class

　　Rewrite the sentences in the Passive Voice.

　　1. You mustn't say dirty words to us.

　　2. We should water plants often.

　　3. Mary may put on her dress tomorrow.

　　4. They can climb that mountain.

　　5. Teacher should correct the homework.

　　6. You must keep the office clean.

　IX. Homework

　　1. Review the contents of Checkpoint 11.

　　2. Finish Exercises 4 and 5.

探究活动

　　主题班会

　　组织一次以“绿色”为主题的班会。可以让同学们简单介绍一下身边的绿化情况。或者针对将在中国举行的2008年奥运会，以及北京提出了“绿色奥运”的口号，让同学们就此发表一些个人见解或者提出一些建议。

　　资料查找及整理

　　组织同学们到图书馆查找关于国外植树造林或保护环境的资料，然后分组整理出关于这方面的英语文章，要有一定的说服力，并且内容真实严谨。是一篇完整的语篇，上下文连接要紧密，并说明一定的道理，有教育意义。

　　In developing countries people mostly use wood for cooking and heating. They cut down trees for fuel. But a tree cools the land under it and keeps the sun from smaller plants. As the leaves fall, they enrich the soil. When trees disappear, smaller plants die and only sand remains. Yet people need fuel, animals, and crops in order to live.

　　Men can take deserts, but they can also prevent them from getting bigger. Algeria(阿尔及利亚) is planting a green belt of trees along the edge of the Sahara Desert(撒哈沙漠) to stop the sand. In China, too, windbreaks(防风林带) are being built in the northwest to keep the desert from growing.

　　But deserts still threaten the world. Experts believe that land that is on the way to becoming

　　desert equals the size of Australia, Russia and the United States put together. Can we stop the spread of the world's deserts and save the land that is so essential to mankind? Yes, we can. And we must.

　　学写议论文

　　【说明】写一篇大约一百二十个英文字 (words) 的短文, 阐述你对知识的看法。

　　【大纲提示】

　　1. 破題：知识之于人就如同罗盘之于船

　　2. 借題：有了罗盘船才能安全橫渡茫茫大海

　　3. 铺路：知识带来力量，有助于改善生活

　　4. 具体举例1：知识有助于发明机器

　　5. 具体举例2：知识有助于艺术创作

　　6. 具体举例3：知识也有助于食衣住行

　　7. 小结：知识使人类生活方便和精神丰富

　　8. 反面举证1：沒有知识人类会变笨

　　9. 反面举证2：沒有知识人类会回到原始时代

　　10. 反面举证3：沒有知识人类无法继承传统

　　11. 总结1：越多知识，越多智慧

　　12. 总结2：人类不能沒有知识

　　【范文】Knowledge

　　Knowledge is to us what a compass is to a ship.  A ship has to rely on a compass to sail safely across an unknown ocean. Similarly, knowledge brings forth power we need to make real progress toward a better life.  With knowledge, we can invent new and useful apparatus and  machines; we can create beautiful art, including paintings, sculpture, music, and so forth; we can make clothes, furniture, cars, space shuttles and the like.  It is knowledge that enables us humans to lead a convenient and colorful life.  On the contrary, were it not for knowledge, people would become stupid and uncivilized; everything would get back to the primitive age; no more human history could be passed down.  In short, the more knowledge we gain, the wiser we will become.

　　 That is, knowledge is indispensable to mankind. (138 words)

　　一、用字解析：

　　1. compass （罗盘）

　　They walked in the forest with a small compass.

　　2. rely on [upon] （信仰）

　　I rely on you to help me.

　　3. bring forth （引起）

　　April showers bring forth May flowers.

　　4. make progress（前进；进步）

　　The ship made slow progress through the canal.

　　She has made a lot of progress in English.

　　5. apparatus[单数集合名词]（仪器）

　　Our school has excellent experimental apparatus.

　　6. including（包括）

　　Ten persons were injured, including three children.

　　7. and so forth [= and so on = and the like]（等等）

　　They discussed literature, philosophy, history, and so forth.

　　8. lead（过；度）

　　After his father's death, he led a life of poverty for several years.

　　9. on the contrary（相反地）

　　I thought it was going to clear up.  On the contrary, it began to rain.

　　10. get back [= return ]（回到）

　　They have got back to Taipei.

　　11 . primitive（原始的）

　　Primitive man made himself primitive tools from sharp stones and animal bones.

　　12.