教学目标
教学目标与要点
1．掌握本单元的有关栽树的方法、程序以及一些有关植树的日常用语和句式。如：The more, the better. It’s best to do sth 等。
2．掌握本单元的词汇，特别是短语so that, beep… from…, thanks to, more or less等的用法。
3．掌握含有情态动词被动语态的构成形式及其肯定、否定和疑问形式。同时还要学会英语中关于长、宽、高、深等的表达方式。
4．学会写notice，要注意它的格式和组成部分。可参考Lesson 44。
5．认真学习“The Great Green Wall”，理解它的重要性，进一步确立Work hard to make our world more beautiful!的观念。
教材内容分析
本单元围绕“植树”这个话题，学习和了解植树的重要性及如何栽树。课文“The Great Green Wall”讲述了森林对人类的重大作用。通过学习课文和对话，进一步复习、归纳了被动语态的用法，重点学习了含有情态动词的被动语态的构成，讲述了英语中长、宽、高的表示方法，学习了一些常用词汇和日常交际用语及重点句式：The more, the better；教会了我们如何书写notice。
本单元词组及日常交际用语
（一）本单元词组与短语
1．Tree Planting Day 植树节
2．neither…nor… 既不……也不……
3．It’s best to do sth. 最好做……
4．knock…in to… 把……插进……里
5．make sure 确保，查明
6．so that 以便，以致
7．several times 多次
8．tie …to… 把……系到……
9．keep…straight 使……直立
10．the Great Green Wall 绿色长城
11．hear of 听说
12．keep…from doing… 阻止，防止
13．run away 逃走，流失
14．rain drops 雨点，雨滴
15．wash away 冲走
16．the dead leaves 枯叶
17．stay in one place 留在一处
18．in this way 用这种方法
19．millions off 几百万的
20．blow away 吹走，刮走
21．move towards… 向……移动
22．the rich farmland 富饶的农田
23．all over the world 世界各地，遍及全世界
24．ask sb. about sth. 询问某人关于某事的情况
25．the more, the better. 越多越好
26．in a few years’ time 几年的时间之后
27．this year alone 只就今年一年
28．be covered with 用……覆盖
29．point to 指向
30．thanks to 幸亏；由于
31．far away 遥远
32．at the right time 适时
33．out of class 在课堂以外
34．hand in 交上来
35．more or less 大约
36．fill…with… 用……填满
37．notice to the audience 听众须知
38．Children under 1.2 m in height 身高不足1.2米的孩子
39．keep off 避开，防止
教学建议
本单元重点例句及相关知识的讲解
1. Come to school in your old clothes tomorrow.
明天请穿旧衣服来学校。
英语中表示“穿”的词有wear, put on, have on, dress, be in, etc. 它们的具体用法如下：
wear, have on和be in强调状态，wear有时可用进行时态；put on强调动作；dress既可表示状态，也可表示动作, dress后不直接跟表示服装、鞋、帽等名词，而其他所列名词后跟服装鞋帽等名词，be in后可接表示颜色的名词。例如：
Lucy is too young to dress herself. Tom was putting on his trousers when Lucy called him. Tom pushed the door and asked, “Do you know Kate?” Lucy answered, “I’ve know the girl in red before. ” Kate was in a red coat when she came in. She helped Lucy to dress. Everything is ready now. Lucy is wearing a new hat. Tom has on a black coat.
露西太小了，不能给自己穿衣服。露西喊汤姆时，他正在穿裤子。汤姆推门问：“你认识凯特吗？” 露西回答：“我以前就认识那个穿红衣服的女孩儿”。凯特进来时穿着一件红色的外套。她来帮露西穿衣服。现在一切就序，露西戴着一顶新帽子。汤姆穿着一件黑外套。
2. The ground must be just right——neither too wet nor too dry.
土壤一定要正好，既不能太湿，也不能太干。
just right 正合适； neither…nor…既不……也不……，它可以连接两个主语、表语、宾语，还可以连接两个状语等，当它连接两个主语时，谓语动词应根据就近原则，即在人称和数上与后面的一个主语保持一致。
The driver drives neither slowly nor quickly.
那司机开车既不慢，也不快。（连接状语）
The old man can neither see nor hear.
那老人既看不见，也听不见。（连接谓语）
Bill has neither brothers nor sisters.
比尔既没兄弟，也没姐妹。（连接宾语）
Neither he nor I am a teacher. 或
Neither I nor he is a teacher.
他和我都不是教师。（连接表语）
Neither they nor Mary is going to the zoo tomorrow. 或
Neither Mary nor they are going to the zoo tomorrow.
他们和玛丽明天都不去动物园。（连接主语）
注意：neither和of连用，后接物主代词、名词等限定的复数名词时，其谓语动词用单数形式；另外，neither的意思是“两者中任何一个都不”，指人或指物，是单数概念，用于没有冠词、物主代词，指示代词等限定的单数名词前，其谓语动词用单数形式。例如：
Neither of the flowers is beautiful.
两朵花都不好看。
Neither of them is teacher.
他们俩都不是老师。
Neither story is interesting.
两个故事都没有趣味。
Neither answer is right.
两个答案没有一个是正确的。
I like neither school – bag.
两个书包我都不喜欢。
3. Dig a hole large enough for the tree.
给树挖一个足够大的坑。
enough“足够的”，修饰形容词或副词时，要放在被修饰词之后；修饰名词时，可以放在名词前也可以放在名词后。
My brother has enough money /money enough to buy his own car now.
我兄弟有足够的钱可以买一辆自己的小汽车。
He is tall enough to reach the apples on the tree.
他够高的了可以够到树上的苹果了。
Li Ming is studying hard enough to catch up with other students.
李明学习很努力可以追上其他同学了。
4. Knock a long, strong stick into the earth in the hole.
在坑里插入一根长而粗的棍子。
knock sth. into… 把……插进（钉进）……，knock at (on) 敲……；另外knock into可以表示“碰撞”解。例如：
Don’t knock the nail into the chair.
不要把钉子钉进椅子里去。
Listen! Someone is knocking at (on) the door.
听！有人在敲门。
The young man knocked into me yesterday.
昨天那年轻人撞了我。
5. Made sure that it is straight.
确保树是直立的.
make sure表示“弄确实；核实；查证”。make sure常用于祈使句，后面常接that宾语从句或of介词短语。Make sure + that从句意为“弄明白；确信”。Make sure + of + 代词/名词，意思也是“弄明白；确信”。例如：
— Make sure of his coming before you set off.
— I make sure (that) he would come.
— 出发之前要确定他是否来。
— 我确信他会来。
另外，be sure + 不定式大多数情况下也用于祈使句，表示“务必；一定要；不要忘记”。
例如：
Be sure to come to our party if you have time.
如果有时间的话请一定来。
Be sure to finish the work as soon as possible.
请务必尽快完成这项工作。
6. Tie the tree to the top of the stick to keep it straight.
把树系在棍子的顶部让他直着。
(1) tie v.“系上”；n.“领带，领结”；tie…to…意为“把……系在……”。
She tied his horse to a tree by the road.
他把马拴在路旁的一棵树上。
She bought a tie for her husband yesterday.
她昨天给她丈夫买了条领带。
(2) to keep it straight 是动词不定式，在句中作状语，表示捆树的目的。keep it straight 为“动+ 宾 + 宾补”结构，如：
You'd better keep your room clean. 你最好使你的房间保持清洁。
Don't touch the machine. You must keep yourselves away from any danger. 别动机器，你该保证自己的安全。
7. But more “Great Green Walls” are still needed, and not only in China.
但是，更多的绿色长城仍旧需要，这不仅在中国。
not only 能常和but also连用，意思是“不但……而且……”，可以连接两个主语、谓语、宾语等，当连接两个主语时，谓语动词应和第二个主语在人称和数上保持一致，also往往可以省略。例如：
She is good at not only dancing but (also) singing. She is both a dancer and a singer.
她不但善长跳舞，而且善长唱歌。（连接两个宾语）她是个舞蹈家和歌唱家。
Not only you but (also) your sister has to get to school on time. Being on time is a must.
不仅你而且你妹妹都得按时到校。守时是必须的。
8. Many thousands of trees must be planted every year.
每年必须种植成千上万棵树。
（1）thousands of这种类型的结构前面已讲述过，它的前面不可用具体的数字，可用不确定数目的修饰语，如some, many, several等。
Some hundreds of people watched the match.
好几百人观看比赛。
（2）plant / grow
这两个动词都有“种”的意思，区别如下：
1) plant“种植”，及物或不及物均可，常指移植已长成秧苗的植物，可用于“plant+场地+with”结构。如：
They planted trees in the garden. = They planted the garden with trees. 他们在花园里种树。
April is time to plant. 四月是种植季节。
2）grow“栽培；（人或草本等）生长”，及物或不及物均可，常指使某种植物从种子起在某地生长，不移走。如：
They grow roses in the greenhouse. 他们在温室里栽培玫瑰花。
Do all plants grow from seeds? 所有的植物都从种子长成的吗？
3) 指种植花草，用grow或plant均可；指种植树木，一般用plant；指种植农作物，用grow。如：
We have grown / planted a lot of flowers this summer. 我们夏天栽培了许多花。
People in the south grow rice. 南方人种植水稻。
9. The more, The better.
越多越好。
So the more trees there are, the better harvests we have.
因此树木越多，我们的收成也越好。
the +比较级 + …，the + 比较级 +…。这个句型的意思是“越……，越……”。例如：
The busier the farmers are, the happier they feel. The more students read, the better their English will be. The longer plant grows, the better.
农民们越忙越高兴。学生读得越多，他们的英语会越好。庄稼的生长期越长，长得越好。
10. In a few years’ time, those mountains will be covered with trees, too.
几年之后，那些山上也将栽满了树。
in a few years’ time意思是“几年时间之后”，类似的用法还有：In two days’ time, in three months’ time等。例如：
In two days’ time, the work will be finished.
两天的时间，就能完成此项工作。
11. Was it difficult to work on the Great Green Wall?
从事绿色长城工作难吗？
It + is / was + 形容词 + 不定式。这种句型中不定式是真正的主语，it是形式主语。例如：
It’s best to plant trees in spring.
最好在春季植树。
It’s best to read English every day.
最好每天读英语。
It’s interesting to play games with Children.
和孩子们一起做游戏是很有趣的。
12. But thanks to the Great Green Wall, the land produces more crops.
但是幸亏有绿色长城，土地长出了更多的庄稼。
thanks to幸亏，由于。thanks为名词，常用复数。例如：
Thanks to your help, we were successful. Thanks to the policeman, the old man was brought home.
由于你的帮助，我们成功了。多亏了警察，老人被送回了家。
13. The Great Green Wall is 7, 000 kilometres long, and between 400 and 1, 700 kilometres wide.
绿色长城有7000公里长，400到1700公里宽。
（1）计量的表达法是：
主语+ be+数词+metres / kilometers + long/ wide/ high/ tall/ deep等形容词。例如：
The river is about 100 metres deep. The mountain is nearly 4, 000 kilometres high.
这条河大约有100米深。这座山有近4000米高。
Our classroom is ten metres long and seven metres wide.
我们的教室十米长，七米宽。
（2）分数表达法：分子用基数词计数，分母用序数词计数，同时分子是1以上的数字，分母用复数形式；分子为1时，分母采用单数形式。l/2:one second; l/3:a third; 2/5:two fifths等。特殊的表达法有：a half, a quarter, three quarters等。
14. — Is it straight?
— More or less!
— 它直吗？
— 有一点儿直!
more or less“差不多；大概”相当于about。
The road is two hundred metres long, more or less.
这条路大概有两百米长。
The exercises are more or less finished.
作业快要做完了。
15. Children under 1.2m in height can not be taken into the concert hall.
1.2米以下的孩子禁止带入会场。
height 为名词，形容词为high. 1.2 m in height 意为 1.2m high。如：
— What is his height？
— He is six feet in height (＝He is six feet high．)
— 他有多高？
— 他有六英尺高。
关于含有情态动词的被动语态的讲解
※含有情态动词的被动语态的构成
前两个单元已学过一般现在时态和一般过去时态的被动语态的构成，以及被动语态的用法。本单元学习含有情态动词的被动语态。它的构成形式是：情态动词+ be + 动词的过去分词；否定式是在情态动词后 + not, 疑问式是将情态动词放于主语之前。情态动词有：can, may, must, school, could, have to等。例如：We must find out the truth . → The truth must be found out .
（1）The trees must be planted in spring.
树必须春天栽。
（2）May the exercises be done tomorrow?
练习可以明天做吗？
（3）Books can not be taken out of the reading-room.
书不能带出阅览室。
（4）These young trees should be watered every day.
这些小树应每天浇水。
（5）The sick person need be taken good care of.
那病人需要很好地照顾。
（6）Your bike has to be mended well.
你的自行车需好好修修了。
※ 被动语态与系表结构的区别
动词 be + 过去分词这个结构并不定都是被动语态结构，有时它可能是 be + 过去分词 ( 作表语 ) 的系表结构。因此：
be + 过去分词 ( 被动语态 ) 与 be + 过去分词 ( 作表语 ) 这两种结构的主要差别是：
①被动结构表示一个动作，带表语的结构表示主语的特点或所处的状态。如：
The library is now closed . ( 系表结构 )
It is usually closed at 6 . ( 被动结构 )
②被动结构后面可带 by + 实施动作者，而系表结构一般没有。如：
The glass is broken . ( 系表结构 )
It was broken by my sister . ( 被动结构 )
③“系表结构”中的过去分词可以被 well , very 等副词修饰，而“被动结构”中的过去分词则一般不能如此。如：
The book is well written . ( 系表结构 )
The book is written by Li Ming . ( 被动结构 )
④被动结构可以用于许多时态之是，而系表结构只用于一般现在时和一般过去时这两种时态。如：
The work is being done . ( 被动语态 )
The work is done . ( 系表结构 )
⑤系表结构有主动意义，而被动结构只有被动意义。被动结构的句子往往有表示动作的时间、地点、方式、目的等状语，而系表结构一般没有这样的状语。如：
The photo was taken last month . ( 被动语态 )
The photo was well taken . ( 系表结构 )
本单元的有关听说读写的教学建议
◆有关听说方面的教学建议
本单元第41课以Read and act的形式来引出本课的教学重点。教师应充分利用这个对话情景，进行对话表演，以提高学生的兴趣，达到自然地呈现新课的目的。
教师在上课时，可穿一件旧衣服或工作服，问学生，“I came to school in/I'm wearing my old clothes today. Tomorrow you will come to school in your old clothes. Do you know why?” 这时，学生们可以进行多种猜测。在学生情绪高涨时，教师让他们带着问题听课文录音。在听第一遍录音后，利用本课挂图，再让学生听一至两遍录音。为了帮助他们更好地理解对话的内容和句型，教师此时可将一些关键词写在黑板上，如：: in old clothes, What's happening? Tree Planting Day, Really? Wonderful! 在学生了解了对话的基本内容后，教师可放录音让全班跟读或分角色对话。然后两人一组借助黑板上的关键词来复述或表演。注意这段对话的主要目的是引出下面的“instructions”，而且对话中新的语言知识不多，所以不必占用过多的时间。
在进行了一定的pair work 之后，教师可以要求学生进行表演练习。出示关于植树过程的一组图，让学生回忆植树的经过和步骤，在教师的引导之下，用英语将这些步骤表达出来。
如：How to choose the ground?
What should we do for the first step? Dig a hole or knock a stick into the earth?
What should we do for the second step? Knock a stick into the earth or put the tree into the hole?
What should we do next? Put the tree into the hole or put the earth back into the hole?
What should we do next then? Push the earth down hard?
Tie the tree to the stick or water the tree well. which step comes earlier?
通过上述问题的问答，学生就基本上明白了植树的步骤。然后要求学生在小组内进行口头的表达，要求学生能够比较流利的表达植树的过程。
第44课在Read and act下也有3段对话。但与第41课对话不同。这时学生已学完本单元的语法重点和阅读文章。这3段对话设计的目的在于巩固学生所学的知识，并提供不同情景引导他们实际应用。教师可设计如下3幅简笔画。
教师可分段放录音或在课前事先安排3位学生与教师配合表演这3段对话。然后进行全班、半班或两人一组的练习。教师分段抽查数组表演情况。在学生已基本能分别表演3段对话的基础上，让他们将3段对话串在一起进行表演，教师可用简笔画或手势、动作来提示学生。
最后教师应鼓励学生实际应用所学知识，如让学生根据第41课的 “instructions”，依照第44课的3段对话，自编对话，进行表演。以下4组对话包括了instructions中所有的注意事项，并尽量使用带情态动词的被动语态。如：
1. A: Will you help me plant this tree, please?
B: Of course/Certainly. What do you want me to do?
A: Well, dig a hole large enough for the tree. But don't dig the hole too deep/the hole should not be too deep.
B: OK. I've dug a hole. It’s just right.
2. A: Good. That's done. Hold this stick while I knock it in.
B: OK. Make sure that it is straight.
A: Is it straight (now)?
B: More or less!
3. B: What's next?
A: Put the tree in the hole now/The tree must be put in the hole now.
B: OK. I've done that.
A: Right. I'll put the earth back in the hole again while you hold the tree straight. Then, let's push the earth down hard with our feet several times.
4. B: Good. Now the tree must be tied to the top of the stick to keep it straight.
A: OK. While you're doing that, I'll go and get some water.
B: OK. But can we go and have a drink after that?
A: A drink? We've only just started! There are twenty more trees to be planted.
(Certainly. Let's go. But we have twenty more trees to be planted. )
◆有关读写方面的教学建议
在阅读的教学过程中，一定要重视语篇的教学，也就是说，在教学的过程中，教师不要过分的强调句子的结构或者是过分的强调句子的语法功能分析，而忽略了文章的本来面目。例如，文章的结构，文章的主题句，文章的基本段落的中心意义等。允其要引导学生将文章中的个别句子放在上下文的语境中进行准确理解。在教学本单元阅读课文时，教师首先要让学生了解课文大意，然后帮助学生分段理解，并可划分段落，找出主题句(topic sentence)。在本课结束时，学生应能复述课文。
在阅读前，教师可设置如下问题，让学生猜测并讨论，以引起他们的阅读兴趣。
What's the Great Green Wall?
Where does China build the Great Green Wall?
What does the Great Green Wall do?
在学生讨论过程中，教师可利用学生用书第III页彩图和教师用书提供的材料 (Notes)，适当给学生们补充一些背景知识 。
T: Sanbei shelter-forest (三北防护林) is known as China’s “Great Green Wall”. It is a “Great Green Wall” of trees, millions of trees. China has built a new Great Green Wall across the northern part, including Inner Mongolia, Shanxi, Hebei, Beijing and Tianjin. The Great Green Wall also covers some of the Northwest (Xinjiang, Qinghai, Gansu, Ningxia and Shanxi) and the western part of the Northeast (Liaoning, Jilin and Heilongjiang). It includes altogether 13 provinces, cities and autonomous regions (自治区). Its total area is 4, 069, 000 square kilometres, which cover 42.4% of the land of China. The building of the Great Green Wall will take 73 years (1978—2050). The Great Green Wall has already saved a lot of land by stopping the wind from blowing the earth away and the sand from moving towards the rich farmland in the south. But more “Great Green Walls” are still needed not only in China but all over the world.
教师在介绍背景知识时，可借助中国地图、手势等使学生大致了解，必要时可用汉语解释。文中划线句子为课文中原句或对原句稍加改动的句子。教师在讲到这些句子时可适当强调、重复，以加深学生的印象。
然后让学生打开书阅读课文。在确知大部分学生已基本掌握课文大意的情况下，要求他们划分课文段落并找出每个段落的主题句 (topic sentence)。然后对文章进行段落的划分。然后让学生归纳出每个段落的大意。
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. |
|
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。