Lesson Twenty-nineTrees Make Cents

Guide QuestionsAnalysis and ExplanationReading ComprehensionSummary of The Lesson

Guide Questions Did 14-year-old Candice Ray take an active part in an en

vironment campaign called “Beat the Heat”? Was Candice very much concerned about how to keep p

eople cooler in summer and warmer in winter? What is Candice’s solution to global warming , pollution

and carbon dioxide in the air? What are the results of a new study on trees conducted

by the U.S Forest Service? How do trees lower the air temperature? Why is CO2 sometimes called a “greenhouse” gas? Why can trees be considered as pollutant filters ? What’s the girl’s basic view in this article?

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Money really does grow on trees .A new study on trees has showed that trees make good economic sense both by making it less costly to heat and air-condition buildings and by reducing air pollution.

Obviously,trees not only provide shade to help cool us in summer but block cold winter winds as well.That saves money on air-conditioning and heating costs and the fuel it takes to power cooling and heating systems.

Moreover, they make the oxygen we need to breathe without extra expenses and help counteract the “global warming”.Most important of all, trees soak up countless other pollutants like smoke, ozone,and particulate matter.With more trees,we’ll have cleaner, fresher air to breathe, and a healthier planet to live on.

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Trees Make Cents

Plant a tree : it will keep you warm in winter ,cool in summer, and help you save money all year round .

Money really does grow on trees. That ’s a message 14-y

ear old Candice Ray of Mew Haven, Connecticut , could have used when she testified before Congress two years .

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“ I wanted Washington to know my fears about global warming , pollution , and especially my fears about all the carbon dioxide in the air,’’ says Candice, who testified as part of an environmental campaign called “Beat the Heat .’’ Her proposed solution : Get people to care about trees ,Earth’s natural air conditioners and pollution filters . “Unless more people care about saving trees,’’ Candice says, problems like pollution and maybe global warming “will get worse .’’

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The results of a new study on trees may help boost Candice’s argument —— and hit members of Congress where they ’ll feel it : in the wallet . The study , conducted by the U.S. Forest Service , found that trees make good economic sense . “ Trees can actually save cities millions of dollars each year by making it less costly to heat and air-condition buildings, and by reducing air pollution,’’ says Greg McPherson of the Forest Service .

If , like Candice ,you want to convince some difficult-to-inspire adults , here are some facts from the study to back up these claims:

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First ,there’s the obvious. Trees provide shade to help cool us in summer . And they block cold winter winds . That saves money on air-conditioning and heating bills and the fuel it takes to power cooling and heating systems .“By planting three mature trees for shade and windbreak ,”says McPherson, “a home owner can save $ 50 to $90 per year on air-conditioning and heating costs alone .’’, Over time the money saved would far exceed the cost of the trees .

All Natural AC But there ‘s more to the cooling effect of trees than simple

shade .Trees provide natural air-conditioning through a process called evapotranspiration, or “tree sweating .”

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We perspire , trees transpire —— give off moisture when they get hot . Perspiration and transpiration both produce a cooling effect when the moisture evaporates —— changes from liquid to gas . Why ? Because this phrase change requires energy .

When you sweat, the energy required for evaporation comes from your body as heat . So evaporating sweat “pulls’’heat from your body .

But trees don’t have warm bodies like us .So their evaporating “sweat” pulls heat from the surrounding air .That lowers the air temperature so you can turn down the AC. Money in the bank !

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OXYGEN PUMP The coolest part is that while trees are doing all that coo

ling , they’re also making the oxygen we need to breathe. The process is called photosynthesis , a series of chemical reactions trees use to make their food .Basically, leaves take in carbon dioxide ( CO2 ) from the air and combine it with water ( H2O) using the sun’s energy .The products :sugar ( C6H12O6) and oxygen ( O2).The reaction looks like this :

CO2+h2O sunlight C6H12O6 +O2 Eventually the trees use the energy in the sugar to build

new leaves ,branches ,and roots in other words ,to grow .

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The more trees grow ,the more energy they need —— and the more O2 they produce .Plus, if you look closely at the equation you ‘ll see that photosynthesis helps use up one of our wastes —— CO2.

We’re not just talking about the CO2 our bodies exhale , but also the many tons of this gas we spew into Earth ‘s atmosphere when we burn fossil fuels , such as oil and coal .Without trees the CO2 in car and factory exhaust would accumulate ,or build up , in our atmosphere .That would be a problem ,scientists say ,because O2( along with some other gases ) forms a layer in our atmosphere that traps the sun’s heat just like a greenhouse ceiling . That ‘s why CO2 is sometimes called a “greenhouse” gas .Some scientists say these gases could eventually trap so much heat that our entire planet will heat up . return

Trees can help counteract this “ global warming” by taking in the CO2 and locking it up in the carbon compounds that makes up their leaves , roots , and trunks .

POLLUTANT FILTERS Trees soak up countless other pollutants too , says McPherson

—— things like smoke , ozone ,and particulate matter . “One large ,healthy tree can save over $2per year in pollution removal,’’ he says . Not impressed ? Try multiplying to see how much money 2000trees would save a city : $4000.

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Of course , adds McPherson , “trees can become stressed if pollution levels get too high .”and stressed –out tress won’t do any of their jobs well .

Which brings us back to Candice’s bottom line : “We need to take care of trees and keep them healthy , so they can keep us healthy ,” she says . “With more trees ， we ‘ll have cleaner ,fresher air to breathe ,and a healthier planet to live on .’’

From Science World , Nov .18, 1994 .

Approximately 800 words

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True or False Candice was allowed to speak before Congress so as to draw th

e government ‘s attention to environmental problems . T When Candice testified before Congress ,she said , “ Money doe

s really grow on trees .’’ F Candice proposed that people plant trees in spring time . F The author of the article doesn’t seem to agree with Candice . F

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Reading ComprehensionReading Comprehension

According to the author trees are important to people in that they are earth’s natural air conditioners and pollution filters .

T Trees can help cool us in summer by providing shade and ta

king in heat from the surrounding air . T Trees can help prevent colder temperatures in winter by for

ming windbreaks to block cold wind . T Trees can help make the environment cleaner by constantly

soaking up CO2 and other pollutants. T

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1.Trees provide natural air-conditioning through a process called_____ .

[A] evaporation [B] perspiration [C] transpiration [D] evapotranspiration key: [D]

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Multiple-choice

2. While trees are doing all that cooling ,they ‘re also making the _____ we need to

breathe. [A] CO2 [B] H2 O [C] O2 [D] C6H12O6

Key: [C]

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3.Trees can soak up countless pollutants except ______ . [A] smoke [B] ozone [C] carbon dioxide [D] nitrogen

Key: [D]

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4 _____ helps use up one of our wastes CO2.

[A] photosynthesis [B] evapotranspiration [C] greenhouse [D] particulate matter

Key: [A]

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5. According to the passage ,we can learn that the tress

use the ____ to build new leaves , branches and roots . [A] carbon dioxide [B] energy in the sugar [C] oxygen [D] energy in the water

Key: [B]

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Questions for discussion

How can trees help counteract this “global warming”?

How can trees keep people healthy?

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Candice Ray of New Haven ,Connecticut : a girl’s name .She is from New Haven, a seaport in south Connecticut, U.S.A

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Unless more people care about saving trees problems like pollution and maybe global warming will get worse.

Here “unless ”means “ if not” instead of “except when ”.

Do not come, unless I call you.

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First, there’s the obvious: First, the fact is very clear. We put a definite article before a noun, “the obvious”, it often means a kind of thing or people.

Soon she will be among the unemployed. 不久，她会成为失业大军中的一员。

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may help boost : may help popularize ( Candice’s argument )

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and hit members of Congress where they’ll feel it : in the wallet: may convince members of Congress that public money can be saved through tree planting .

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Trees make good economic sense : it pays to plant trees .

make sense : “signification 有意义”，前面可以加上限定词， make no sense “ 没有意义”， make good sense“ 有意义

This sentence doesn’t make sense. 这句句子不通。

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Trees can actually save cities millions of dollars each year by making it less costly to heat and air-condition buildings, and by reducing air pollution”.

1 ) “it” 在此句中，是形式宾语，真正的宾语是后面的动词不定式短语。

2 ）句中 heat and air-condition 是名词，这里转化为动词，通过词类转化构成新词的方法叫转类法 ( conversion ) 。

常见的有以下几种类型： a 名词 ___ 动词 b 动词 ____ 名词 c 名词 ___ 形容词 d 形容词 ____ 名词 return

Difficult-to-inspire adults :adults who are reluctant to be convinced and then decide to take constructive actions. 译成：顽固不化分子 . “difficult-to-inspire” 是个复合形容词，等于一个后置的定语从句 who are difficult to inspire. 常见的结构有名词 / 副词 / 形容词 +现在分词与过去分词。

She is an easy-to-persuade woman. 她是个很容易被说服的人。

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block

1 ) n.. lump, street 块 , 街区 I have a huge block of time all to myself .

2 ) vt. Obstruct; hinder 阻挡，妨碍The funds were blocked . 资金被冻结。

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mature 1 ) adj. grown-up a man of mature age 中年人 2 ) v. to bring to full development . 变成熟，到期He matured the novel by constant revision . 他一改再改，使小说日臻成熟。 return

Over time ,the money saved would far exceed the cost of the trees.

1 ) over time : during the course of time .2 ) 在 the money saved 中， saved 是过去分词作定语修饰 the m

oney 。过去分词作定语一般放在所修饰的成分前面，但其意义侧重在被动含义时，通常用作后置修饰语。

1)The Committee has surrendered a written report on the public security. 委员会已经提交了一份有关公共安全问题的书面报告。

2 ) The experiment done has achieved a great success. 实验取得了圆满成功。

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evaporate v.

1 ) to convert or change into vapor 蒸发，挥发We tried to evaporate the contradiction between ends and means

.

我们试图化解目的与手段之间的矛盾。 2 ) to vanish 消失

Dreams quickly evaporate unless we hasten to put them into words .

梦醒后若不马上把梦境形诸言词，很快就会被忘得干干净净。

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Phase change : change of state of matter .

物质状态的改变。

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turn down the AC: reduce the power being used to run the air-conditioner .

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photosynthesis// : 光合作用

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Plus : here the word is used as an adverb, meaning “What’s more ”or “besides.”

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fossil fuels// : 矿物燃料

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Without trees the CO2 in car and factory exhaust would accumulate, or build up, in our atmosphere: If there were not trees ， ---in our atmosphere. 没有树木，小汽车排出的二氧化碳和工厂排出的废气就会在我们的大气中积聚起来。

1)“without trees” 相当于 “ if” 引导的虚拟语气条件句，因此主句用 would + 动词原形，“表示与现在事实相反的情况”。

2)exhaust v. use up The city is small and the delights of tourism there can be exhausted in three days .那个城市很小，值得观光的地方三天就可以游遍。3 ） n. waste gas exhaust pollution 废气污染 4) build up : to develop or increase in stages or by degrees 聚集，集积 clouds are building up over the sea. Enemy forces are building up in that area.

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Trees soak up countless other pollutants too. soak v.

1 ) wet all over 使湿透 A good way to get a stamp off an envelope is to soak it off .

从信封上取下邮票的一个好办法是把它弄湿后揭下。

2 ） to take in or accept mentally 沉湎于 She soaked herself in romantic novel.

她热衷于阅读富有浪漫色彩的小说。3) soak up: take in ;draw 吸收；吸取 This device can soak up the heat of the sun.

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Particulate matter : particles, or extremely small parts of harmful substances in the air.颗粒物质

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Which brings us back to Candice’s bottom line.

1) Which: referring to what is talked about in the above paragraph .

2) bottom line: basic view.

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Outline of the textComment on the story

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A 14-year-old girl states the functions of trees in three respects, that is to say ,trees can be regarded as Earth’s natural air conditioners ,oxygen pump and pollution filters, so we can spend less money on air-conditioning and heating.

With the aid of the girl’s views, the author of this article sound a warning that we should protect our living environment by looking after trees well, which is the duty of our humankind.

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Answer:yes.

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Answer: No, she wasn’t.

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Answer: Get people to care about trees,Earth’s natural air conditioners and

pollution filters. return

Answer: The study found that trees makes good economic sense.Trees can actually save cities millions of dollars each year by making it less costly to heat and air-condition buildings andby reducing air pollution.

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Answer: Trees evaporating “sweat” pulls heat from the surrounding air.

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Answer: Because CO2 forms a layer in our atmosphere that traps the sun’s heat just like a greenhouse ceiling.These gases could eventually trap so much heat that our entire planet will heat up. return

Answer: Trees soak up countless other pollutants,thing like smoke,ozone,and particulate matter.

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Answer: We need to take care of trees and keep them healthy, so they can keep us healthy.

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Answers to the discussion questions.

By taking in the CO2 and locking it up in the carbon compounds that make up their leaves,roots and trunks.

With more trees,we’ll have cleaner,fresher air to breathe,and a healthier plan to live on.

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