Planting trees

　　课文的段落划分和主题句或大意如下：

　　第一段：第l自然段

　　主题句：Forests help to keep water from running away.

　　第一段大意：The importance of forests;

　　第二段：第2—3自然段

　　主题句：Chinese people have built a new Great Wall.

　　第二段大意：Something about the Great Wall in China   

　　第三段：第 4—6自然段

　　主题句：The more trees there are, the better harvests we have.

　　第三段大意：Something about a worker, who works on the Green Great Wall, thinks highly about the Green Great Wall.
教师还可以让学生填写下表：

THE GREAT GREEN WALL

Special features

across the northern part of China，7，0OO kilometres long，between

400 and l700 kilometres wide

Functions

It stops the wind from blowing the earth away; and stops the sand from moving toward the rich farmland in the south. It has saved a lot of land.

Wang Feng and other workers

They work at Yulin in Shaanxi. They have planted ten thousand tree this year. It’s difficult to work on the Great Green Wall. They have to grow their own food.

　　提取主题词（key words）也有助于帮助学生复述课文大意。

Forests

keep from, water, soil, floods

China

copy, across, is…long and between…and …wide, stop…from, save, needed, all over the world

Wang Feng

　　work on…, visit, among, ask, plant, over there, on the hill, five years ago, in a few years’ time, be covered, point to, difficult, grow food, thanks to

　　在进行写作训练时，可以要求学生仿照课文，写一篇以How to plant flowers in the garden 为题目作文。

关于带情态动词的被动语态的教学建议

　　本单元在前两个单元学习一般现在时和一般过去时的被动语态的基础上，继续学习带情态动词的被动语态。 

　　在第41课，以显著的位置展示题为“HOW TO PLANT A TREE”的操作规程（instructions），教师如果仅仅是按部就班地讲解，就会使学生感到枯燥乏味。要充分利用课文中所提供的情景，在有意义的情景中教学语法知识。例如，教师可利用简笔画来引出新的语法知识。学生基本掌握instructions大意后，教师应引导他们理解情态动词的用法。到了第43课可采用对比的方法。教师列出两个框框，要求学生分别填上课文中已出现的带情态动词的句子，和可以由主动语态变为情态动词的被动语态的句子，把变化后的句子填入框内。如下表： 

1. The ground must be just right.

2. But the hole should not be too deep.

1. The earth should be neither too wet nor too dry.

2. A hole must be dug large enough for the tree. The size of the hole must be just right.

3. A long, strong stick should be knocked into the earth next to the hole. It must be firmly planted.

4. The tree must be put in the hole so that it is straight. The tree must stand straight in the hole.

5. The earth must be put back in the hole again.

6. The earth should be pushed down hard with ....

7. The tree must be tied to the top of the stick ....

8. It should be watered well, ....

　　学生在做这个练习时，对本课句型与词汇有了进一步认识，同时也锻炼了写的能力。

　　在有条件的学校可放教学录相以加深印象。在全班读熟课文后，展示几幅植树的图片，让学生独自准备几分钟，进行连锁练习，按次序复述instructions。也可两组之间进行比赛，由A组说出第一条注意事项，再由B组说出下一条。最初可完全复述课文原句。熟练后，可全部用主动语态或全部用被动语态，或一句主动语态一句被动语态交替出现，或句子中带有情态动词等方式进行操练。

关于计量表达法的教学建议

　　本单元第42课教学了计量 (measurement)表达法。

　　表示计量的方法是：数词+metres/ kilometres +long/wide/deep/high/tall…

　　表示重量可用数词+kilograms +heavy.

　　The classroom is 4 metres wide.这个教室有4米宽。

　　The river is about 10metres deep.这条河大约有10米深。

　　教师可利用学生身边的事物教学计量表达法。例如描述教室及桌椅，可说出以下句子：

　　The classroom is 3. 5 metres high, 4. 5 metres wide and 5. 5 metres long.

　　The table is half a metre high.

　　也可以出示一幅世界地图，让学生造句：

　　The Yellow River is 5, 464 kilometres long and between…and…metres deep.

　　Mount Qomolongma is 8848. 13 metres high.

　　The Yangtze River is about 6,300 kilometres long.

　　The lake is between 150 and 250 metres wide.

　　以上例句呈现完毕后，可让学生自己归纳计量表达法的特点，并将它写在黑板上：

　　metre (s) /kilometers + long/wide/deep/high/tall …

　　第43课第一部分和此课练习册 Ex2是为练习计量表达法而设计的。教师还可要求学生造句，造句最多而错误最少的学生将给予奖励。

Lesson 41

Properties: Recorder; Overhead Projector; Pictures

Teaching Objectives: