人教版（2019）选择性必修 第一册Unit 5 Working the Land Evaluate chemical farming预习课件 (21张ppt)

(共21张PPT)
Unit 5 Working the land
Evaluate chemical farming and organic farming
预习课件
essential adj. 及其重要的；完全必要的
教材原句
There is usually more water than essential minerals.
要点必记
essential information 重要信息
essential use 必要用途
essential mineral 主要矿物
核心词汇
alternative n. 可供选择的事物；adj. 可供替代的
教材原句
As an alternative, some farmers have switched to organic farming.
要点必记
alternative method 替代的方法
alternative approach 变换方法
have no alternative but v. 别无选择；只得；唯一的办法是
instance n. 现实；事实
教材原句
For instance, they may grow corn or wheat in a field one year.
要点必记
for instance 例如（for example; such as）
in this instance 在此情况下
at the instance of 在…的请求下；经…的提议；因…的主张
depth 轮流；依次
教材原句
Organic farmers also plan diverse crops that use different depths of soil to help keep it rich.
要点必记
in depth 深入地；全面地
in the depth of 在……里面
long—length wide—width high—height deep—depth
entirely v. 消化；领会
教材原句
Some people would prefer to stop the use of man-made chemicals in agriculture entirely.
例句
Their price depended almost entirely on their scarcity.
他们的价格几乎完全靠他们的供不应求。
This administration is not entirely free of suspicion.
这届政府并不是完全没有疑点。
not only…but also
要点必记
1. not only…but also就近原则
连接两个主语时，要和与其最近的主语保持人称和数的一致。
如：
Not only Tom but also Alice and Mary are busy.
不仅汤姆很忙，爱丽丝和玛丽也很忙
核心句式：
为了强调，可将not only置于句首，其后的句子通常要用部分倒装的形式。
如:
Not only has she been late three times, she has also done no work.
她不仅仅迟到了3次，她还没干一点活。
Unit 5 Working the land
Evaluate chemical farming and organic farming
1
Learn more about the advantages and disadvantages of chemical farming and organic farming.
Words: digest; essential; mineral; alternative; grocery; depth; root
2
Phrases: for instance
3
Goals
Look and discuss
What is the advantages and disadvantages of chemical farming
Lead in
Learn
Read the text and answer the question.
1. Why did many farmers welcome the introduction of chemical farming
2. What concerns many people about the use of pesticides
3. What is one problem with the use of chemical fertilisers
It is a great way to fight crop disease and increase production.
It may make them ill and even cause cancer.
Crops grow too fast to be rich in nutrition.
Learn
4 How is organic farming different from chemical farming
5 Why do organic farmers change the kind of crop grown in a field every year
6 What is the goal of using organic farming methods
Organic farming is without any chemicals.
They put important minerals back to the soil
To grow good food without damage the environment of people’s health.
Learn
2. Match the main ideas (A-D) below with the paragraphs. Then complete the
sentences in the table.
A What organic farming is
B Why man-made chemicals are still used in farming
C Organic methods for producing rich soil
D The problems with chemical farming
Paragraph Main Idea
1-2
3
4
5
Learn
D
B
A
C
Detail
Pesticides can kill helpful______________.
Some pesticides have been _______ because of the_____
crops grown with chemical fertilisers usually _________ to
full of_______.
Many organic farmers use ____________ as fertiliser.
They often ____________ grown in each field_______.
They also plant crops that use __________ of the soil to
help keep it rich.
Organic farming is nowhere near able to meet the need
bacteria and insects
damage
prohibited
nutritions
grow too fast
natural waste
corn or wheat
one year
different depths
Learn
3. Write an argumentatives essay giving your opinion on chemical or organic farming.
Discuss these questions in groups.
Is the author of the passage for or against organic farming How do you know
What other disadvantages of chemical farming did the author not list
How might the following items be problems and how important are they for organic
farming
natural animal waste used as fertiliser
higher cost of producing food
greater effort required to farm
What other disadvantages of organic farming can you think of
Decide whether your group supports chemical farming or organic e up with three main points to support your opinion, and then add at least one detail to support each main plete the outline below.
In my opinion, ___________ farming is preferable to _____________ farming because
(Detail)
(Detail)
(Detail)
Learn
organic
chemical
Keep soil rich
Free of diease
Rich in minerals
Use this checklist to help you review your partner's draft.
Does the writer do a good job of expressing his/her opinion
Does each paragraph have one main idea
Does each paragraph have at least one detail to support its main idea
Does the writer sequence the points in a logical order
Does the writer do a good job persuading you to accept his/her opinion
Learn
Summary
Phrases
Words
Phrases: in turn
Words: digest; essential; mineral; alternative; grocery; depth; root
预习 Unit 5 Review the whole unit。
3
1
Recite new words and phrases.
2
Write an article about whether we should use chemicals in farming.
Homework
Bye-bye!