台大外語教學暨資源中心英語學習報

 

Autumn Leaves Show Their True Colors

秋葉本色


Watch on VOA

“Green leaves are yellow. You just don’t see the yellow.”

「綠色的葉子本來就是黃的,只是你沒看到而已。」


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自學包裹(Self-Study Package)中高級第60期上線了!!

第60期自學包裹簡介

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本期也把文章中的學術字彙抓出來當成重點字彙練習。AWL字彙表由570word family(包含一個字的詞類變化與衍生字)組成。經過研究發現,這570個字群是橫跨各領域學術的高頻率單字,已經是目前國際高等教育的英語教學的重要參考資料。同學只要熟練AWL字彙表與其衍生字,就可以用最少的力氣,讀懂各領域的文章,吸收新知。

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MyET台大外語教學暨資源中心Speaking Proficiency Test競賽

競賽時間:10/17-10/28、11/14-11/25、12/5-12/16

本學期提供口說能力檢測競賽,一共有3個場次,歡迎台大學生來加強英文口說能力,我們提供MyET線上互動英文口語教材。經由專業的線上英文會話機制及分級化教化,協助不同程度的訓練、改善英文發音及腔調,道地說英文。詳情請見網頁


MyET台大外語教學暨資源中心單字TOEFL&GRE學習競賽

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「先聽說、後讀寫」是學好 一種語言最有效的方法;結合先進科技和專業語言教學法的MyET-MyCT,提供一個以聽說訓練為主的語言學習環境,讓學習者透過「眼看、耳聽、口說」學習模式有效培養聽力、改善發音與腔調,迅速提昇口說能力,終極聾啞英語的弊病。不論您是否已經安排了國外旅遊還是在世界任何角落,都可以透過有網路連線的電腦,每天跟著進度參加比賽喔! 詳情請見網頁

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紐西蘭英文老師架設的網站,從2006年開始,至今已提供了1000多場show,每場約5分鐘,將網路上的熱門話題、歌曲中的口語英文等,用淺顯易懂的英文影片介紹給大家。請不要錯過喔!

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在這個國際化的年代,各領域都相繼舉辦國際研討會以期跟國際學界最新潮流接軌;既然是國際會議,想當然爾官方語言大部分是英文啦。一般的英文大家都會,但 是!如果今天要擔任工作人員需要宣布事項該怎麼講?遇到心儀的學者該如何寒暄?討論時間想提問或發表意見又該怎麼說呢?這時候就讓我們來看……咦?沒什麼 機會參加國際會議,所以這東西跟你無關?同學且慢且慢~現在有越來越多課程都是用英語授課,老師們為了訓練同學的英語能力,甚至會安排同學帶討論或者舉辦 模擬會議喔!這種時候 MyET所提供的國際會議演講英語課程就可以派上用場啦!趕快一起來看看這個課程到底有些什麼~


一群高中生,聽說了一名學生和家人一起出城渡假的消息,那些高中生闖入那名同學的家中,舉辦了一場喧鬧瘋狂的派對,他們之所以會得知這家人全家出遊,原因是那名學生在自己的facebook動態消息中公布了這項訊息,這種過度分享的行為,是社群媒體迅速普及之後,一種令人憂心的附產品,詳情請看 Advanced English  2011 - 10月號!

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全民英檢考題改版了!要考全民英檢的同學,熟悉新型式的考題是重要的準備工作。外語教學中心新增了許多"新"全民英檢的考試書籍,同學透過按部就班的練習,對通過檢定很有幫助。其中這一套《新全民英檢中高級教室-聽/說/讀/寫全測驗》,作者在取材方面力求多元,在模擬試題中也可體會學英語的樂趣喔。


 英語宅急便     

November 15, 2011
Shelley Schlender | Boulder, Colorado

As days grow shorter and nights grow cooler in Boulder, Colorado, the green leaves of summer have been putting on party colors.

On cottonwood trees and aspens, they’re golden yellow coins. On Mapleton Avenue, the maple trees are sunset shades of orange and red.

The same seasonal phenomenon occurs in many countries in late autumn, yet people don't always know the reason leaves change color when the weather gets cooler.

Fall splendor

Some do have their theories about the autumnal transformation.

“I’ve heard that the reason why the leaves change throughout the seasons is because God likes to see different colors all over the world," says one girl, "so that he can tell what season it is.”

“According to legend," says a woman, "three hunters and their dog chased the Great Bear into the sky, slaughtered it and its blood dripped onto the leaves, turning them red.”

Dave Sutherland, a naturalist with Boulder Mountain Parks, recalls the explanation he heard in childhood. “My mom told me it was because at night, when everybody’s asleep the fairies come out and paint them.”

Magical science

It turns out the scientific explanation for why leaves change color is almost as magical as artistic fairies.

The story begins in summer, when leaves are green thanks to a pigment known as chlorophyll. It captures just the right spectrum of color from the sun’s light, to power the process known as photosynthesis.

As the days grow shorter in autumn, leaves stop making chlorophyll, revealing a dazzling secret: green leaves are actually yellow.
VOA - S. Schlender
As the days grow shorter in autumn, leaves stop making chlorophyll, revealing a dazzling secret: green leaves are actually yellow.

“As the chlorophyll is grabbing that sunlight, it’s pulling water from the soil and carbon dioxide from the air and energy from the sunlight and shoving it together to make sugar,” Sutherland says.

That helps the tree blossom and grow. As the days grow shorter in autumn, leaves stop making chlorophyll, revealing a dazzling secret.

Dazzling secret

“Green leaves are yellow. You just don’t see the yellow," Sutherland says. "The yellow pigments are there all along, hidden beneath the mask of green. They’re just waiting for a chance for the chlorophyll to start breaking down so the yellow color can start shining through.”

That yellow comes from pigments known as carotinoids, which make carrots orange and autumn aspen leaves golden yellow. Some scientists say leaves keep making carotinoids after they’re done with chlorophyll, because the yellow pigments help them capture a little more solar energy.

And when they turn red? That’s another pigment called anthocyanin.

“Everybody knows anthocyanin," Sutherland says. "It makes strawberries red and blackberries black.”

And fall maple leaves red.

Natural sunscreen

But, unlike carotinoids, leaves don’t make this pigment during summer, only in autumn. For decades, scientists believed anthocyanin made a sort of accidental color, caused by sugars trapped in dying autumn leaves.

But Bill Hoch, a plant scientist at Montana State University, is among those who believe leaves make anthocyanin on purpose, as a kind of natural “sunscreen.” As an autumn leaf loses its ability to make energy from photosynthesis, he says, the red anthocyanin pigment protects the leaf from the harmful effects of sunlight - especially the blue spectrum of light.

This helps the leaf’s energy-making machinery stay intact just long enough to send the last bits of nutrients, especially nitrogen and phosphorus, into the tree’s twigs and roots.  

“It’s only to recover those nutrients, because those leaves are going to be discarded pretty quickly," Hock says. "So they’re just trying to protect their photo systems long enough to just recover as many nutrients as possible.”

Hoch adds that carotinoids protect the photo systems, which are light-powered energy cells. But instead of being a sunscreen for the final days of a dying leaf, the yellow pigment is an anti-oxidant that protects the leaf throughout its life.

As for why some leaves turn yellow and others turn red, Hoch says plants that grow best in full sun tend to have more robust leaves. So, in the fall, they can get by with the protection of just the yellow carotinoids. Plants that thrive in shade or in nutrient-poor soil tend to have more delicate photo machinery, which need more protection, so their leaves make more anthocyanins and turn dark.  

There’s much more that scientists want to learn about how leaves work.  In the meantime, people in Boulder - and across the northern hemisphere - can simply enjoy the natural splendor of spectacular autumn colors.


Language Notes

aspen (n) 山楊

shade (n) 陰涼處;(色彩的)濃淡,色度
本文中兩種意思都有出現,”sunset shades of orange and red”是指「黃昏時的橘紅色彩」;"Plants that thrive in shade"則是「在陰涼處成長的植物」。

legend (n) 傳說
文中使用片語結構 “according to legend”,「根據傳說」。由於不是指某個特定的傳說,所以這裡把legend當不可數名詞使用。

slaughter (v) 殺戮,屠殺

fairy (n) 小妖精

到了秋季,本來翠綠的樹葉漸漸換上不同的顏色。三角葉楊(cottonwood tree)與山楊(aspen)的葉子如黃金色硬幣(golden yellow coins),但楓樹(maple tree)葉子呈現的是如日落的橘紅相間色彩(sunset shades of orange and red)。這同樣的季節現象(seasonal phenomenon)在很多地方會發生,但背後卻會被賦予不一樣的故事。有的神話說(according to legend),因為獵人把大熊(星座)趕到了天上後殺了它(slaughter),它的血滲出而沾染到樹葉上(dripped onto the leaves),所以就把樹葉都變紅了。自然學家(naturalist) Dave Sutherland 則回憶起小時候媽媽的解釋,是小精靈(fairies)在大家睡著的時候把葉子給漆紅的。

pigment (n) 顏料;色素

chlorophyll (n) 葉綠素

dazzling (a) 使目眩的;使讚歎不已的
文裡 “
dazzling secret”一詞的使用巧妙的結合了dazzle的兩個含意,指樹葉「光彩奪目而令人讚嘆的秘密」。

shove (v) 亂塞;強使

blossom (v) 開花;生長茂盛

葉子變色後面科學的解釋也如神話一樣充滿魔力。從夏天開始,葉子會呈現綠色是因為含有葉綠素(chlorophyll)這個色素(pigment),功用是捕捉到太陽光光譜裡對應的顏色(captures just the right spectrum of color form the sun’s light),進而可以進行光合作用(photosynthesis)。葉綠色抓住了太陽光的能量,連同土壤裡吸取的水,空氣裡的二氧化碳,全都混在一起後就產生了糖(shoved it together to make sugar)。

break down (v phr) 失敗; 崩潰

carotinoid (n) 類胡蘿蔔素 *carotene 胡蘿波素

anthocyanin (n) 花青素

Sutherland說到,「其實綠色葉子本就是黃色的,只是沒被看到而已。黃色色素一直都存在於葉子裡(. . .are there all along),只是被藏在綠色的掩罩之下(hidden beneath the mask of green)。直到葉綠素開始瓦解了(break down),黃色才能真的透出光來」。黃色是來自於葉子裡的類胡蘿蔔素(carotinoid)色素。有科學家提出解釋,當葉子停止生產葉綠素後(done with chlorophyll),類胡蘿蔔素還能再多捕捉一點的太陽能。而讓葉子變紅的則是花青素了(anthocyanin)。草莓呈現紅色,黑莓呈現黑色都是花青素的功勞。

on purpose (prep phr) 故意;有目的地

intact (a) 完整無缺的

discard (v) 拋棄,摒棄

robust (a) 強健的;茁壯的

hemisphere (n) (地球的)半球

葉青素只有在秋天產生,這跟在夏天時就開始被製造的類胡蘿蔔素不同。科學家們多年來認為葉青素其實是種「意外的」顏色(accidental color),是因為糖份被困在秋天漸漸死去的葉子裡所造成的(caused by sugars trapped in dying autumn leaves)。但有植物學家則認為葉子製造葉青素是有意義的(on purpose)。葉青素是葉子的一種天然「防曬劑」(sunscreen),當葉子無法再透過光合作用產生能量的時候,葉青素可以保護葉子免受到陽光的傷害,尤其是光線裡的藍色光譜(the blue spectrum of light)。如此一來,葉子的能量製造機制(energy-making machinery)還能保持完整(intact),可將最後一點養份(nutrients)送回到樹木的枝枒(twigs)和根部去。

科學家們對於葉子到底是如何運作的還有很多需要傷腦筋的地方。但對北半球的人來說(people across the northern hemisphere),只要單純來享受自然壯麗的秋天景色就好了(the natural splendor of spectacular autumn colors)。

 

 
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