科技英語閱讀李健

1、Unit 1 EnvironmentEarths Health in Sharp Decline, Massive Study Finds大規(guī)模研究發(fā)現(xiàn)：地球的“健康”每況愈下The report card has arrived from the largest ever scientific Earth analysis, and many of the planets ecosystems are simply not making the grade.有史以來對地球進行的最大規(guī)模的科學(xué)分析結(jié)果表明，地球上的許多生態(tài)系統(tǒng)都達不到標(biāo)準(zhǔn)。The UN-backed Millennium Ec

2、osystem Assessment Synthesis Report found that nearly two-thirds of Earths life-supporting ecosystems, including clean water, pure air, and stable climate, are being degraded by unsustainable use.由聯(lián)合國主持的千年生態(tài)系統(tǒng)評估綜合報告指出，由于不可持續(xù)的使用，地球上將近三分之二的用來維持生命的生態(tài)系統(tǒng)（包括干凈的水源、純凈的空氣以及穩(wěn)定的氣候）正遭受破壞。Human has caused much o

3、f this damage during the past half century. Soaring demand for food, fresh water, timber, fiber and fuel have led to dramatic environmental changes, from deforestation to chemical pollution, the report says. The already grim situation may worsen dramatically during the first half of the 21st century

4、, the reports authors warn.以上大部分的破壞都是人類在過去的半個世紀(jì)里造成的。據(jù)報告分析，隨著人類對食物、淡水、木材、纖維以及燃料等資源的需求日趨激增，環(huán)境發(fā)生了極大的變化，引發(fā)了諸如濫伐森林、化學(xué)污染等問題。因此，該報告的作者警告說，照此下去，本已岌岌可危的生態(tài)環(huán)境將會在21世紀(jì)的上半葉進一步惡化。Over 1,300 governmental and private-sector contributors from 95 countries collaborated to create the landmark study. For four years they

5、 examined the plants many habitats and species and the systems that bind them together. The United Nations Environment Programme compiled the report and released the results yesterday in Beijing, China.這項歷史性的研究由來自世界95個國家的政府部門以及民間組織的1,300多位科學(xué)家共同完成。四年來，他們考察了地球上許多生物的生長環(huán)境、物種以及將他們聯(lián)系起來的生態(tài)體系。聯(lián)合國環(huán)境規(guī)劃署對該報告進行

6、了編輯整理并于昨天在中國北京公布了研究結(jié)果?！癘nly by understanding the environment and how it works, can we make the necessary decisions to protect it,”UN Secretary General Kofi Annan said in a press statement accompanying the reports release.“Only by valuing all our precious natural and human resources, can we hope to b

7、uild a sustainable future.”在公布該報告的新聞發(fā)布會上，聯(lián)合國秘書長科菲·安南指出：“只有了解環(huán)境及其運作過程，我們才能制定出必要的措施加以保護它?！彼€說，“只有珍惜所有寶貴的自然資源和人類資源，我們才有希望去建設(shè)一個可持續(xù)發(fā)展的未來?！盨ocioeconomic Impact對社會經(jīng)濟的影響The report paints a rather bleak picture for biodiversity throughout much of the natural world. Perhaps 10 to 30 percent of earths mam

8、mal bird and amphibian species are facing extinction.該報告對自然界的大部分生物多樣性持悲觀態(tài)度，地球上可能有10%30%的哺乳動物，鳥類以及兩棲動物瀕臨滅絕。The massive ecological survey was begun in response to Annans Millennium Development Goals, a UN initiative that aims to dramatically reduce socioeconomic problems, such as hunger and extreme po

9、verty, by 2015.這次大規(guī)模生態(tài)調(diào)查是根據(jù)安南的千年發(fā)展目標(biāo)展開的，該發(fā)展目標(biāo)是由聯(lián)合國發(fā)起的，旨在2015年之前大幅減少饑餓與極度貧困等社會經(jīng)濟問題?！癟he Millennium Ecosystem Assessment give us, in some ways for the first time, an insight into the economic importance of ecosystem services and some new and additional arguments for respecting and conserving the Earth

10、s life-supporting systems.”said Klaus Toepfer, executive director of the Nairobi-based UN Environment Programme.總部位于內(nèi)羅畢的聯(lián)合國環(huán)境規(guī)劃署執(zhí)行主席克勞斯·托普弗說：“從某些方面來說，千年生態(tài)系統(tǒng)評估綜合報告讓我們首次認識到生態(tài)系統(tǒng)服務(wù)功能的經(jīng)濟價值，并使我們對尊重和保護地球生命維護系統(tǒng)有了新的見解?！盋urrent human usage patterns of Earths environment have increased the global food sup

11、ply, albeit too slowly to accomplish the UN goal of halving word hunger by 2015.目前由于人類社會對地球環(huán)境的開發(fā)利用，食物供應(yīng)不斷增加，然而增長的速度仍然太慢，難以完成聯(lián)合國制定的在2015年之前消除全球一半饑餓人口的目標(biāo)。The negative effects of ecosystem strain also include collapsing fisheries, coastal“dead zones” near sediment-heavy river mouths, shifting water qua

12、lity, and unpredictable regional climate, the report says.報告還說，過度使用生態(tài)系統(tǒng)的負面影響還包括漁業(yè)的衰退，含有大量沉積物的河口周圍近海“死亡區(qū)”的出現(xiàn)，水質(zhì)的變化以及不可預(yù)測的區(qū)域性氣候等。 Deforestation and other radical ecosystem alterations also promote disease, such as malaria and cholera, as well as new strains of existing contagions.此外，森林的濫伐和其他生態(tài)系統(tǒng)的

13、巨大改變也加劇了諸如瘧疾、霍亂等疾病的傳播，并使已有傳染病分化出新的類別。 Changes to water systems may increase the frequency and severity of destructive floods. Over a hundred thousand people were killed in the 1990s by floods, which also caused destruction to the tune of 243 billion dollars (U.S.), according to the report.根據(jù)該報告

14、，水資源體系的變化會增加毀滅性洪災(zāi)的爆發(fā)頻率和程度。在20世紀(jì)90年代，洪災(zāi)造成的死亡人數(shù)超過10萬，損失約2,430億美元。 The regions facing the greatest environmental degradation are also among the worlds poorest: sub-Saharan Africa, Central Asia, and parts of Latin America, and South and Southeast Asia.目前，世界上環(huán)境破壞最嚴重的地區(qū)恰是全球最貧窮的地區(qū)：撒哈拉沙漠以南之中部非洲地區(qū)，亞洲中部，

15、拉丁美洲的部分地區(qū)，以及亞洲的南部及東南部。Call for Radical Change呼吁徹底改變現(xiàn)狀 The report urges drastic policy changes to the ways in which natural resources are used.千年生態(tài)系統(tǒng)評估綜合報告呼吁在自然資源利用方面對目前的政策進行大幅度的改變。 From an economic perspective, the study suggests that many intact ecosystems should be regarded as more valua

16、ble than those altered for comical use.該研究認為，從經(jīng)濟角度看，與那些被用于商業(yè)開發(fā)的生態(tài)系統(tǒng)相比，很多完整生態(tài)系統(tǒng)的價值更高。 For example, citing wetland wildlife habitat, water pollution filtration, water storage and recreational value, the report appraised intact Thai mangroves at a thousand U.S. dollars per acre (0.4 hectare). The

17、same mangroves were valued at only U.S. $200 an acre after they had been cleared for fish and shellfish farming.例如，該報告通過對濕地野生動植物的生境、水污染過濾情況、水資源儲存能力以及娛樂價值等方面的分析，估算出保護完整的泰國紅樹每英畝（0.4公頃）價值為1,000美元，而同樣的紅樹，由于漁業(yè)及貝類養(yǎng)殖業(yè)的開發(fā)而遭到了破壞，其價值僅為每英畝200美元?！癟he overriding conclusion of this assessment is that it lies with

18、in the power of human societies to ease the strain we are putting on the nature services of the planet, while continuing to use them to bring better living standards to all,” the reports 45-person board of directors said in a statement.由45位成員組成的研究委員會在一份聲明中指出，“這個評估報告最重要的結(jié)論是，如何在利用地球生態(tài)系統(tǒng)提升人類生活水平的同時，緩解我

19、們對其所施加的壓力，這完全取決于我們?nèi)祟惿鐣！?#160;“Achieving this however will require radical changes in the way nature is treated at every level of decision-making and new ways of cooperation between government, business and civil society,” the statement continued. “The warning signs are there for all of us to see. T

20、he future now lies in our hands.”該聲明還指出：“但是，要達到上述目的，需要徹底改變?nèi)藗儗Υ匀坏姆绞?，小到各級決策的制定，大到政府、商業(yè)和文明社會之間新的合作。警鐘已經(jīng)敲響，未來掌握在我們自己手里?！?#160;The board of the Millennium Ecosystem Assessment Synthesis Report was co-chaired by Robert Watson, chief scientist of the World Bank, and A. Hamid Zakri, director of the United

21、Nations University Institute of Advanced Studies.擔(dān)任千年生態(tài)系統(tǒng)評估綜合報告委員會主席的是世界銀行的首席科學(xué)家羅伯特·沃森和聯(lián)合國大學(xué)高等研究所主任A. 海米德·扎卡雷。 Unit 2 Energy SourcesThe Future of Alternative Energy替代能源的前景Residential energy use in the United States will increase 25 percent by the year 2025, according to U.S. Depa

22、rtment of Energy (DOE) forecasts. A small but increasing share of that extra power will trickle in from renewable sources like wind, sunlight, water and heat in the ground.據(jù)美國能源部預(yù)測，至2025年美國的家用耗電將增加百分之二十五，增加的電量中將有一小部分來源于再生能源（如風(fēng)、陽光、水、地?zé)幔疫@部分還會不斷增大。  Last year alternative energy sources provided

23、 6 percent of the nations energy supply, according to the DOE.據(jù)美國能源部統(tǒng)計，去年替代能源占整個國家能源供給的百分之六。 “The future belongs to renewable energy,” said Brad Collins, the executive director of the American Solar Energy Society, a Boulder, Colorado-based nonprofit organization. “Scientist and industry expert

24、s may disagree over how long the worlds supply of oil and natural gas will last, but it will end,” Collin said.美國太陽能協(xié)會（該協(xié)會是一個位于科羅拉多州博德市的非盈利性組織）的主管布拉德柯林斯說：“未來屬于可再生能源。盡管就世界石油和天然氣可以持續(xù)多久，科學(xué)家和工業(yè)專家可能有不同觀點，但是油氣資源終將耗盡。”  While renewable energy is generally more expensive than conventionally produced su

25、pplies, alternative power helps to reduce pollution and to conserve fossil fuels. 盡管可再生能源通常比傳統(tǒng)能源更昂貴，但是替代能源有助于減少污染、保護礦物燃料。 “People sometimes get caught up in cost-effectiveness,” said Paul Torcellini, a senior engineer at the DOEs National Renewable Energy Laboratory(NREL) in Golden, Colorado. “

26、But it can be a question of values and what we spend our money on.”美國能源部國家再生能源實驗室（位于科羅拉多州戈爾登市）的一位高級工程師保羅陶塞列尼說：“有時人們考慮的只是節(jié)省成本的問題，但是這可能是一個價值觀念的問題，一個我們把錢用于何處的問題?！?#160; Below, a look at some recent developments in renewable-energy technology:接下來我們一起了解關(guān)于可再生能源技術(shù)的新發(fā)展 Solar Power太陽能  Photovoltaic

27、, or solar-electric, systems capture light energy from the suns rays and convert it into electricity. Today these solar units power everything from small homes to large office buildings.光電系統(tǒng)獲取太陽光線的光能并將其轉(zhuǎn)化成電。現(xiàn)在這些太陽能設(shè)備可以為各種建筑供電，小到家庭大到辦公樓。 Technological improvements have made solar-electric module

28、s more cost-effective. In the 1980s the average price of energy captured with photovoltaic was 95 U.S. cents per kilowatt-hour. Today that price has dropped to around 20 cents per kilowatt-hour, according to Collins, of the American Solar Energy Society.技術(shù)進步使得光電設(shè)備更加劃算。20世紀(jì)80年代，光電系統(tǒng)供電的平均價格為每千瓦時95美分；而

29、根據(jù)美國太陽能協(xié)會的統(tǒng)計，如今這一價格已降至每千瓦時20美分左右。  The cheaper rate is still more expensive than the average national price of electricity, which in 2003 was a little over 8 cents per kilowatt-hour, according to the U.S. Department of Energys Annual Energy Review.即使略微便宜的光電價格仍然高于全國電價的平均價格，據(jù)美國能源部發(fā)行的能源周刊統(tǒng)計，2003年每

30、千瓦時的電價均價略高于8美分。Other recent advances include “thin film” photovoltaic technology, a high-tech coating that converts any surface covered with the film into a solar-electric power source. Boats and RVs that use the film are now on the market.其他最新的發(fā)展包括薄膜光電技術(shù)，這種高科技的涂層能夠?qū)⑷魏胃采w此類薄膜的表面轉(zhuǎn)化成一種光電電源。使用這種薄膜技術(shù)的輪船和

31、娛樂用車目前已上市銷售。  Engineers have also developed a roofing material coated with electricity-producing film. “The guy who puts on the roof (on a house now) puts on the solar panels at the same time,” Torcellini said. The roofing material withstands inclement weather and, on bright days, taps sunshine

32、 for electricity.工程師們也研究出一種涂有發(fā)電薄膜的屋頂材料。人們在搭建屋頂時，同時就可以放上這種太陽能嵌板，陶塞列尼說道。這種屋頂材料能耐極端天氣，而且在陽光明媚的時候可以利用太陽光發(fā)電。  NREL researchers, meanwhile, are working to devise more efficient and cheaper solar-electric systems. Most traditional photovoltaic solar units on the market today convert between 11 and 13

33、percent of the suns light into energy. Engineers think they can improve on that.與此同時，美國可再生能源實驗室的研究人員正在研發(fā)更為高效、價格更低的光電系統(tǒng)。目前市場上大多數(shù)傳統(tǒng)光電設(shè)備可以將百分之十一至百分之十三的太陽光轉(zhuǎn)化成能量，工程師們認為這一比例還可以再提高。  Jeff Mazer, a Washington, D.C.-area photovoltaic engineer, notes that most thin-film photovoltaic systems today have a

34、7 to 11 percent efficiency rating. But he estimates that thin films could surpass that rating within three years. He also notes that some new traditional solar modules achieve 15 percent efficiency and believes that figure can climb to 17 percent in the near future.華盛頓地區(qū)的一位光電工程師杰夫梅澤說現(xiàn)在的多數(shù)薄膜光電系統(tǒng)的效能等級

35、只有百分之七至百分之十一。然而，據(jù)他估計，薄膜光電系統(tǒng)在三年內(nèi)可以超過這一等級。他還說一些新式傳統(tǒng)太陽能設(shè)備可以實現(xiàn)百分之十五的效能，但他相信這一數(shù)字可以在不久的將來攀升到百分之十七。 In the last two decades solar-thermal panels (units used to warm household hot water, pools and spas) have become highly efficient. “Energy costs have decreased from 60 cents to 8 cents per kilowatt-hou

36、r since the 1980s,” Collins said. 近20年中，光熱板（用于為家庭熱水、水池、泉水升溫的設(shè)備）的效能大大提高?？铝炙拐f：“自20世紀(jì)80年代起，能源成本從每千瓦時60美分降至8美分。”  Solar-powered water heaters are typically more expensive than conventional ones, but, as with other products that harness alternative energy, consumers benefit by knowing their energy c

37、osts up-front Torcellini said. “Otherwise, youre hedging your bets about the future cost of traditional energy sources by using standard appliances,” he said.太陽能熱水器通常比常規(guī)熱水器更昂貴，但是像利用替代能源的其他產(chǎn)品一樣，消費者可以預(yù)先知道其成本從而獲益。陶塞利尼說：“否則，將難以抉擇：是仍然使用普通熱水器，還是致力于降低未來傳統(tǒng)能源的成本?！?#160; Wind Power風(fēng)能  Compare to other re

38、newable energy sources, wind power competes with conventional energy at a price less than 4 cents per kilowatt-hour, according to Collinis.據(jù)柯林斯的說法，與其他可再生能源相比，風(fēng)能更具有競爭力，其每千瓦時的價格比傳統(tǒng)能源低4美分。  Wind energy projects around the world now generate enough energy to power nine million typical U.S. homes, a

39、ccording to the American Wind Energy Association, a Washington, D.C.-based trade group.美國風(fēng)能協(xié)會（一個總部位于華盛頓的貿(mào)易團體）稱目前世界各地的風(fēng)能項目發(fā)電足可以為九百萬典型的美國家庭供電。  One of the newest trends in wind power is the construction of offshore wind farms, cluster of electricity-generating turbines erected in open-water areas

40、 with strong winds.利用風(fēng)能的最新趨勢之一就是建設(shè)離岸海上風(fēng)力發(fā)電廠，在風(fēng)力較大的空曠水域建造一組組的發(fā)電機組。  Europe now has 17 wind farms spinning offshore. The Arklow Bank Offshore Wind Park, 8 miles (13 kilometers) off the eastern coast of Ireland, is one such project. Its seven turbines generate enough electricity to power 16,000 ho

41、mes. While few homes generate their own wind power in the U.S., many power companies allow consumers to opt for power generated at a wind plant or other renewable source.歐洲現(xiàn)在有17個海上風(fēng)力發(fā)電廠在運轉(zhuǎn)。距離愛爾蘭東海岸8英里（13公里）的阿克羅銀行海上風(fēng)力園就是這樣的一個項目，它的七個渦輪機產(chǎn)生的電力足夠為16000戶家庭供電。盡管目前鮮有美國家庭利用風(fēng)能自己發(fā)電，但是許多電力公司允許消費者選擇風(fēng)力供電或者其他可再生能源

42、供電。  On Tuesday, Colorado voters will consider a ballot initiative that would requires power companies to provide 10 percent of their electricity from wind and other renewable sources by 2015.周二科羅拉多州的選民將考慮舉行一次公民投票，要求至2015年電力公司為他們提供的電力中的有10%是來自于可替代能源。  “If that passes, power companies will

43、offer more rebates to homeowners to encourage renewable energy production,” said Sheila Hayter, an NREL senior engineer.美國可再生能源實驗室的一位高級工程師希拉海特說：“如果該投票表決能夠通過，電力公司將能夠給房主提供更多折扣，鼓勵他們使用可再生能源。”  Ground Heat地?zé)?#160;Tapping into the ground offers another option to regulate household heating and cooling

44、.開發(fā)地下能源為調(diào)節(jié)家庭供暖和降溫提供了另一種選擇。  In most areas of the United States, the ground below the frost line maintains an average temperature between 50 and 54 degrees Fahrenheit (10 to 12 degrees Celsius).在美國的大部分地區(qū),冰凍線以下地面的平均溫度保持在50至54華氏度(10至12)。Ground-source heat pumps, also called geo-exchange systems, u

45、se this relatively constant temperature to keep homes at comfortable temperatures. The devices employ a series of underground, liquid-filled tubes or wells. Liquid flows through the pipes into the home, where a heat exchanger either adds or subtracts heat from indoor air, depending on the season. In

46、 winter, that means added warmth captured from the ground. “If you can (do that), your furnace doesnt have to work so hard,” Hayter said.地?zé)岜孟到y(tǒng)，也稱為地?zé)峤粨Q系統(tǒng)，采用這種相對恒定的溫度保證家中的室溫維持在舒適的溫度。這種裝置使用一系列地下液體管或液體井。液體流經(jīng)這個管道進入家中,通過一個熱交換器根據(jù)季節(jié)增減室內(nèi)空氣的熱度。在冬天,這意味著增加了從地面獲得的溫度。海特說，“如果能夠這樣，家中的火爐就不必如此辛苦了”。A U.S. Environmenta

47、l Protection Agency study found that geo-exchange systems can save up to 70 percent of home-heating costs.美國環(huán)保局的研究發(fā)現(xiàn)，地?zé)峤粨Q系統(tǒng)可節(jié)省高達百分之七十的家庭供暖成本。Unit 3 Plants and AnimalsPlant Adaptation植物的適應(yīng)性Like a human being or an animal, a plant must adapt to its environment in order to survive. Survival usually mea

48、ns struggle. It may be hard to think of a plant as “struggling,” yet that is often the case.像人類和動物一樣，植物為了生存也必須適應(yīng)周邊的環(huán)境。生存就意味著競爭，我們很難想象植物之間的競爭。但也就那么回事。A plant, first, must compete with other plants for light, air, soil and water. Second, it must contend with people and animals, who may eat it or make

49、the environment unfit for it to live in. Third, the physical environment itself may be hostile or inadequate to a plants need. Is there enough light, water, air and soil? Is it warm and cool enough for a given plant species?首先，不同的植物之間會爭奪陽光、空氣、土壤和水分。其次，植物也會與那些吃它或者威脅到它生存環(huán)境的人類和動物競爭。再次，植物所處的環(huán)境也可能也是有敵對性的

50、或者不利于其生長的。怎樣才能有足夠的陽光、水分、空氣和土壤？氣溫的冷熱就是植物生長的主要因素嗎？ Light is vital to a plant, especially a green one. Green plants manufacture foodstuffs in sunlighta process known as photosynthesis. Light also affects the rate of water absorption and flower formation.光對于植物來說是最基本的，尤其是對于綠色植物來說。綠色植物在光照下能制造養(yǎng)分這是一種被稱為光合作用

51、的過程，而光也能影響水分蒸發(fā)的速率和花蕾的形成。 Temperature must also be taken into account. If it falls below 1°Celsius or rises above 43°Celsius, serious injury or death results for most vegetation. Temperature also directly influences the formation of seeds and the production of blossoms. It also helps determ

52、ine the geographic distribution of plants.溫度也是必須考慮的因素。對于大多數(shù)植物來說，溫度低于一度或者高于四十三度都會對其造成嚴重的損傷甚至死亡。而溫度也直接影響了種子的萌芽以及開花。當(dāng)然溫度也會決定植物在地理上的分布。Plants cannot survive without water. Many need immense quantities for their development. Therefore, the humidity of atmosphere, the amount of precipitation and the prese

53、nce of streams, lakes and soil moisture are important to plants.沒有水植物也是無法生存的。有些植物的生長過程需要大量的水分，因此潮濕的空氣、大量的降水以及溪流湖泊和濕潤的土壤對于植物都是重要的。Most plants need plenty of air. The atmosphere contains gases that are essential to their life: oxygen, carbon dioxide, water vapor, and nitrogen.大多數(shù)植物需要有足夠空氣。大氣中包含一些對其生命所

54、必要的氣體，包括：氧氣、二氧化碳、水蒸氣和氮氣。 Not only the air itself, but its movementthe windaffects plants greatly. Wind spreads pollen, spores and certain seeds, enabling plants to grow in many places. But a powerful wind may distort or even kill vegetation, particularly trees. It may below away needed soil. Also, w

55、ind increases the rate of evaporation and so may create a water shortage for plants.空氣移動所產(chǎn)生的風(fēng)對于植物也有很大影響。風(fēng)有助于傳播花粉、孢子和種子從而將它們播種在各種地方。但強風(fēng)也有可能折斷或者損害植物，尤其是大樹。而大風(fēng)吹走了一些有養(yǎng)分的土壤，也會加快水分的蒸發(fā)從而使植物處于缺水狀態(tài)。 Soil is extremely important to land plants. A plants development depends in large part on the nature of the so

56、il: its wetness, acidity, minerals and the amount of oxygen it contains.土壤對于陸生植物來說是必不可少的。植物的生長很大一部分需要依靠其土壤的特性：其中包含它的濕度、酸度、礦物成分、含氧量。 A plant is also influenced by other living things with which it competes. It has to withstand parasites, hungry birds and grazing or gnawing mammals. Yet a plant often

57、needs animals to spread its pollen or scatter its seeds.植物生長也會受到其他競爭生物的影響。它必須要經(jīng)受寄生菌、饑餓的鳥類、牛羊等食用葉子的動物對其的影響，但同時植物也需要動物幫助傳播花粉以及播灑種子。The stems and leaves of trees and shrubs show us some of the adaptations that enable a plant to get the maximum amount of light and air.有樹葉和枝干的樹以及灌木向我們展示了它們的適應(yīng)性，這也告訴了我們植物是

58、怎樣獲得最大量的光和空氣的。In such trees as beech, elm, oak, apple and chestnut, there may be shoots that are primarily vertical while others are primarily horizontal. To secure a maximum amount of sunlight, the leaves on the vertical shoots are arranged in spirals so that any given leaf does not shade the leaf

59、next below it on the shoot. Though the buds on a horizontal shoot of these trees may be arranged spirally, the leaves commonly arrange themselves alternately in a common plane on either side of the shoot.和那些山毛櫸樹、榆樹、橡樹、蘋果樹和栗子樹一樣，它們有一些枝芽主要是垂直生長的，另一些是水平生長。為了能獲得最多的陽光，一些垂直生長的枝芽會螺旋纏繞生長以不至于遮擋到自己下邊的葉子。雖然那些水平生長的枝芽上的花蕾有可能被其他枝芽纏繞著，但樹葉會根據(jù)自身環(huán)境的變化調(diào)整自己的生長方向。In many trees that have their leaves placed opposite to each other, each pair occupies the space between the pair immediately below. You ca