The Mysteries of Proanthocyanidin Transport and Polymerization
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中英双语努力奋斗的名言集锦中文努力奋斗的名言生命不在于活得长与短,而在于顿悟的早与晚。
富人靠资本赚钱,穷人靠知识致富。
吃别人所不能吃的苦,忍别人所不能忍的气,做别人所不能做的事,就能享受别人所不能享受的一切。
一件事被所有人都认为是机会的时候,其实它已不是机会了。
富就富在不知足,贵就贵在能脱俗。
贫就贫在少见识,贱就贱在没骨气。
宁可被人笑一时,不可被人笑一辈子。
不识货,半世苦;不识人,一世苦。
我们可以失去童年,但是千万不可以失去童心。
当时间的主人,命运的主宰,灵魂的舵手。
人生的成败往往就在一念之间,但大多数都是一念之差。
年轻是本钱,但不努力就不值钱。
天上最美的是星星,人间最美的是真情。
别人看不起您,很不幸;自己看不起自己,更不幸。
当你将信心放在自己身上时,你将永远充满力量。
每个人都有退休的一天,但并不是每个人都能拥有退休后的保障。
我们人这一辈子不是别人的楷模,就是别人的借鉴。
舍得有限,赢得无限。
计较眼前的人,会失去未来。
一无所有是一种财富,它让穷人产生改变命运的行动。
人有二亩田,白天的一亩田是填饱肚子,晚上的一亩田是耕种自己的未来。
活鱼会逆流而上,死鱼才会随波逐流。
陪孩子读书长大是个人,给孩子观念长大后是人才。
我们穷人要翻身,没有理由讲辛苦;我们穷人要翻身,没有理由讲兴趣。
世界上什么都可以失去,不可以失去希望,世界上什么都可以失去,不可以失去信心。
智者创造机会,强者把握机会,弱者等待机会。
穷人缺什么:表面缺资金,本质缺野心,脑子缺观念,机会缺了解,骨子缺勇气,改变缺行动,事业缺毅力。
世界上最聪明的人是借用别人撞的头破血流的经验作为自己的经验,世界上最愚蠢的人是非用自己撞得头破血流的经验才叫经验。
不要抱着过去不放,拒绝新的观念和挑战。
人往往拿着书籍的东西来判断无知的事物;人往往拿着错误的推论当正确的结论。
与其战胜敌人一万次,不如战胜自己一次。
好学而不勤问非真好学者。
书山有路勤为径,学海无涯苦作舟。
勤劳一日,可得一夜安眠;勤劳一生,可得幸福长眠。
一.劳伦斯·韦努蒂的基本信息及其主张:劳伦斯·韦努蒂 Lawrence Venuti(1953年—)学者,大学英语教授,专职翻译家,美籍意大利人,生于费城南部(此区域居住者多为意大利裔),七十年代早期在天普大学攻读英语文学,1980年获哥伦比亚大学博士学位。
主要著作:主编论文集《对翻译的重新思考:语篇、主体性与意识形态》(RethinkingTranslation: Discourse, Subjectivity,Ideology),(1992)、《译者的隐身一部翻译史》(Translator's Invisibility: A History ofTranslation)(1995)《不光彩的翻译》(The Scandals of Translation: Towards anEthics of Difference)(1998).韦努蒂把解构主义的翻译思想付诸实施,提出了反对译文通顺的翻译策略。
其目的是:在思想意识上反对殖民主义的翻译观和英美民族中心主义和帝国主义文化价值观;在翻译原则和方法上,提创“存异”而不是“求同”。
通过对英美翻译历史的研究,他得出英美文化中译者和译作实际上处于“隐形”状态。
造成译者隐形的原因是由于归化翻译是英美翻译界的主流翻译方法所致。
鉴于归化翻译是英美翻译作品是主流翻译方法,而译者在这些翻译作品中都是“隐形人”。
Venuti主张“异化”翻译,号召译者采取抵抗翻译策略,以显示自己在翻译中的存在。
Venuti的异化翻译法归因于19世纪德国哲学家Schleiermacher的翻译论说:the translator leaves the author in peace, as much as possible, and moves the reader towards him. “译者尽量不惊动原作者,让读者向他靠近。
”VENUTI异化翻译理论中存在的问题:由于Venuti过分关注政治对翻译方法的影响,其所提倡的异化翻译理论忽视了文学翻译的主要目的,没有考虑到接受者的需求。
神秘的事物英语作文英文回答:Mysteries are captivating enigmas that have intrigued and fascinated us for centuries. They lurk in the shadows, whispering secrets that tempt our curiosity and ignite our imagination. From ancient riddles to unsolved crimes, mysterious phenomena pique our interest and challenge our understanding of the world.One such mystery that has captivated generations is the Bermuda Triangle, an enigmatic region of the Atlantic Ocean where ships and planes have inexplicably vanished. Theories abound, from alien abductions to geological anomalies, but the truth remains elusive, leaving the Bermuda Triangle shrouded in an aura of intrigue.Another enduring mystery is the Loch Ness Monster, a legendary creature said to inhabit the depths of Loch Ness in Scotland. Despite numerous expeditions andinvestigations, the existence of "Nessie" remains unproven, fueling speculation and feeding the imaginations of countless enthusiasts.Beyond the realms of physical phenomena, mysteries also manifest in the realm of the mind. The human psyche is a labyrinth of secrets, with hidden thoughts, emotions, and motivations that can confound and intrigue. Dreams, intuition, and unexplained connections between people have long fascinated psychologists and philosophers alike, hinting at the existence of hidden dimensions within our consciousness.The allure of mysteries lies in their power to stimulate our curiosity and challenge our beliefs. They serve as catalysts for exploration, discovery, and innovation. By unraveling mysteries, we expand our knowledge, deepen our understanding of the world, and satisfy our inherent thirst for knowledge.However, not all mysteries are meant to be solved. Some secrets are destined to remain forever enigmatic,preserving a sense of wonder and inspiring awe. The enigmatic nature of existence itself, with its cosmicorigins and ultimate fate, is perhaps the greatest mysteryof all, reminding us of our humble place in the vasttapestry of the universe.中文回答:神秘事物像迷人的谜题,几个世纪以来一直吸引着我们。
神秘冒险之旅的作文英语Title: A Mysterious Adventure Journey。
As the sun dipped below the horizon, casting long shadows across the rugged landscape, I embarked on a journey into the unknown. It was a quest fueled bycuriosity and a thirst for adventure, a journey that would take me to the far reaches of imagination and beyond.The path ahead was shrouded in darkness, illuminated only by the faint glow of distant stars. Each step I took echoed in the stillness of the night, a rhythmic beat that propelled me forward into the heart of the unknown.As I ventured deeper into the wilderness, the world around me seemed to transform. Trees whispered secrets in the wind, their branches reaching out like skeletal fingers grasping at the sky. The air crackled with energy, a palpable sense of anticipation that sent shivers down my spine.Suddenly, I stumbled upon a hidden pathway obscured by overgrown foliage. Intrigued, I pushed aside the tangled vines and stepped into a realm untouched by time. Ancient ruins loomed in the distance, their weathered stones whispering tales of a forgotten civilization.With each passing moment, the sense of mystery grew stronger, drawing me further into its embrace. I wandered through crumbling corridors and winding tunnels, each twist and turn revealing new wonders and dangers alike.At long last, I emerged into a vast chamber bathed in ethereal light. Before me stood a towering statue, its eyes gleaming with an otherworldly brilliance. I approached with caution, my heart pounding in anticipation of what I might discover.As I reached out to touch the statue, a surge of energy coursed through my veins, filling me with a sense of purpose unlike anything I had ever known. It was as if I had unlocked a hidden power within myself, a connection tosomething greater than myself.With newfound confidence, I pressed onward, guided by an inner voice that urged me forward. Each obstacle I faced only strengthened my resolve, fueling my determination to uncover the secrets that lay hidden within the depths of this mysterious realm.In the end, it was not the destination that mattered, but the journey itself. For in those fleeting moments of adventure, I had discovered a truth that transcended words—a truth that could only be found in the heart of a mysterious adventure journey.。
小学上册英语第一单元期中试卷英语试题一、综合题(本题有100小题,每小题1分,共100分.每小题不选、错误,均不给分)1. A ______ (青蛙) can leap far distances.2.My favorite subject in school is ______.3.She is a scientist, ______ (她是一名科学家), who researches plants.4.The chemical symbol for iridium is _____.5.The process of sublimation turns solid directly into ______.6.The __________ is a large reservoir in the United States. (胡佛水坝)7.What do you call the study of living things?A. BiologyB. ChemistryC. PhysicsD. AstronomyA8.The __________ (历史地图) shows how borders have changed.9. A __________ (元素周期表) helps classify elements based on their properties.10.The horse neighs when it is _________. (兴奋)11.The _____ (栖息地) of many animals relies on plants.12. A _____ (种植计划) helps organize garden activities.13.The chemical formula for propylene glycol is ______.14.We go ________ (shopping) every Saturday.15.Hydrochloric acid is a strong _____.16.What do we call a book written about someone's life?A. FictionB. BiographyC. AutobiographyD. NovelB17.What do you call a baby elephant?A. CalfB. FoalC. CubD. KidA18.I enjoy writing stories. It allows me to use my imagination and create new worlds. One story I wrote was about __________, and it was a lot of fun!19.Which sound does a dog make?A. MeowB. MooC. BarkD. QuackC20.What do we call a scientist who studies the effects of pollution?A. Environmental scientistB. EcologistC. BiologistD. ChemistA21.The _______ (猴子) swings from branch to branch effortlessly.22.What is the main source of light during the day?A. MoonB. StarsC. SunD. FireC23.Which month has Halloween?A. JulyB. OctoberC. DecemberD. JanuaryB24.I enjoy ________ (玩耍) with my friends.25.She has a _______ of books.26.Which fruit is known as the "king of fruits" in some cultures?A. MangoB. DurianC. BananaD. AppleB27.The Great Lakes are located in _______.28.What is the opposite of fast?A. SlowB. QuickC. RapidD. Swift29.I enjoy coloring with my ____ crayons. (彩色铅笔)30. A _____ (植物传统) can be passed down through generations.31.The bat sleeps upside _____.32.Carbon dioxide is produced during ______.33.What do you call a person who studies the weather?A. MeteorologistB. ClimatologistC. GeologistD. PhysicistA34.What is the name of the famous dessert made of layers of filo pastry?A. TiramisuB. BaklavaC. CheesecakeD. GelatoB Baklava35.What is the main diet of herbivores?A. MeatB. PlantsC. InsectsD. FishB36.I love to play games with my __________. (弟弟)37.What do we call a sweetened beverage made from tea?A. Iced TeaB. Sweet TeaC. LemonadeD. Fruit Punch38.The boy plays the ________.39.Matter is anything that has ______.40._____ (农业创新) drives progress in food production.41.What do you call a person who studies marine life?A. Marine BiologistB. OceanographerC. AquaristD. ZoologistA42.My brother is my adventurous _______ who loves to explore.43.What is the name of the fairy tale character who has long hair?A. MulanB. RapunzelC. ArielD. Belle44.The ______ (海狮) barks and plays in the water.45.My dog has a _______ (特别的) collar.46.My _____ (舅舅) is visiting next month.47.The chemical symbol for potassium is ______.48.Which of these is a mode of communication?A. TelepathyB. PhoneC. DanceD. Art49.She is ___ a picture for her mom. (drawing)50.What do we call the process of a caterpillar becoming a butterfly?A. MetamorphosisB. TransformationC. EvolutionD. DevelopmentA51.What is the name of the famous ship that sank in 1912?A. LusitaniaB. TitanicC. BritannicD. Queen MaryB52. A viper is a type of ______ (蛇).53.The _____ is a region of space with a lot of stars.54.The ________ was a significant period of artistic achievement.55.My cousin is a ______. She loves animals.56.The chemical formula for methane is _____.57.What is the name of the famous British author known for his detective novels?A. Agatha ChristieB. J.K. RowlingC. Charles DickensD. George OrwellA Agatha Christie58.The ancient Greeks held their games every four years in ______ (奥林匹亚).59. A bird builds its _______ high in the trees.60.The ______ (小鸟) sings sweetly every morning. I love to listen to its ______ (歌声).61.What is the value of 12 ÷ 4 + 2?A. 4B. 5C. 6D. 7B62.The chemical reaction that releases energy is called _______.63.The __________ (自然灾害) can affect many lives.64.The ______ (小鱼) swims gracefully in the tank.65.What do we call a baby frog?A. TadpoleB. FryC. CubD. KitA66. A _______ is a type of chemical bond that involves sharing electrons.67.The kitten chases after a _______ (小猫追逐一只_______).68.What kind of animal is a frog?A. MammalB. BirdC. ReptileD. AmphibianD69.小狼) howls at night. The ___70.What is the main color of the grass?A. BlueB. YellowC. GreenD. Red71. A process that involves a change in state is called a ______.72.The elephant's large ears help it to cool off in the ________________ (热) sun.73.What do we call a period of ten years?A. CenturyB. DecadeC. MillenniumD. Era74. A __________ is a mixture that consists of two or more substances that retain their properties.75.The first man to sail around the world was _______ Magellan.76. A ______ (鼹鼠) digs tunnels underground.77. A ________ (植物观察小组) shares knowledge.78.My dog loves to play with ______ (其他动物).79.The _____ is the temperature of space.80.He _____ (plays/played) video games all day.81.The main gas used in balloons is __________.82.The suffragette movement fought for _______ rights.83.I like to bake ______ (蛋糕) for special occasions.84. A ______ (植物的研究) can lead to new discoveries.85.I like to run in the ______ (公园) every morning to stay fit.86.I have a _____ (map) of the city.87.The _____ (cup) is full of water.88.How many hours are there in a day?A. 12B. 24C. 36D. 48B89.What do you call a person who studies the earth and its features?A. GeographerB. GeologistC. BiologistD. Astronomer90.The process of sedimentation allows particles to ______ out of a solution.91.What do we call the system of government in which power is held by the people?A. MonarchyB. DictatorshipC. DemocracyD. OligarchyC Democracy92.The turtle can live for many _________. (年)93.My favorite animal is a ______ (猫) that purrs softly.94.I enjoy creating art with my toy ________ (玩具名称).95.We will go _____ tomorrow. (shopping)96.What is the name of the fairy tale character who leaves a glass slipper?A. Snow WhiteB. CinderellaC. RapunzelD. Sleeping Beauty97.What is the largest planet in our solar system?A. EarthB. SaturnC. JupiterD. Mars98.What do we call the animal that is often kept in cages and can talk?A. DogB. ParrotC. CatD. Hamster99.On weekends, I often go _______ (购物) with my family.100.What is the name of the sweet treat made with cream and sugar?A. PuddingB. FlanC. CustardD. Whipped CreamC。
奇妙的探险之作文英语Title: An Extraordinary Adventure。
Embarking on a journey into the unknown is like diving into a sea of endless possibilities, where every wave carries a tale waiting to be unraveled. I recently found myself engulfed in such an adventure, one that swept me away into realms I had never imagined.It all began on a crisp autumn morning, the air tinged with anticipation and excitement. Armed with a backpack filled with essentials and a heart brimming with curiosity, I set out on a path veiled in mystery. The destination? A remote corner of the world whispered to hold secrets beyond comprehension.As I ventured deeper into the wilderness, the surroundings morphed into a kaleidoscope of colors and sounds. The rustle of leaves beneath my feet, the melody of birdsong overhead, each moment was a symphony orchestratingthe narrative of my expedition.The terrain presented challenges at every turn, testing my resolve and igniting a flame of determination within. Scaling treacherous cliffs, forging through dense forests, each obstacle conquered brought me closer to the essence of adventure itself.But it was not merely the physical landscape that captivated my senses. Along the way, I encountered beings whose existence defied logic and reason. From mystical creatures whispered of in ancient folklore to sentient beings dwelling in the shadows of reality, each encounter was a glimpse into a world beyond comprehension.Yet, amidst the awe-inspiring wonders, there lurked dangers unseen and trials unfathomed. It was in these moments of adversity that I discovered the true measure of courage and resilience. With every setback, I rose stronger, fortified by the knowledge that every obstacle was but a stepping stone on the path to enlightenment.As days turned into weeks and weeks into months, my odyssey evolved into a quest for understanding, a pilgrimage to unravel the mysteries of the universe. Each revelation uncovered was a fragment of a puzzle, gradually piecing together the tapestry of existence itself.And then, just when I thought I had reached the zenith of my expedition, fate unveiled its final revelation. A hidden sanctuary nestled amidst the peaks of an untouched mountain range, a sanctuary rumored to hold the key to unlocking the secrets of creation.With bated breath and trembling anticipation, I crossed the threshold into the heart of the sanctuary. What I beheld within transcended the boundaries of comprehension, a symphony of light and sound dancing in harmony with the rhythm of the cosmos.In that moment, I understood. The true essence of adventure lies not in the destination, but in the journey itself. It is a testament to the boundless curiosity that drives us to explore, to seek, and to discover.As I bid farewell to the sanctuary and began my journey homeward, I carried with me not only memories etched in the annals of time but also a newfound appreciation for the wonders that lie beyond the realm of understanding.For in the end, it is not the destination that defines us, but the journey we undertake to reach it. And in the grand tapestry of life, every adventure, no matter how extraordinary, is but a single thread weaving its way into the fabric of eternity.。
the mysteries of the maya课文The Mysteries of the MayaExtending south from parts of what we now know as Mexico into Central America, Maya civilisation(surround) bymystery since its rediscovery in the 19th century. The Maya built.. (impress) palaces and temples.is most extraordinary about these complex structures is how they were built without the use of wheels, metal tools or even animal power. Theyapplied their understanding of mathematics and astronomythe Maya calendar, which was accurate to within 30 seconds per year. On top of all this was an achievement unique in the Americas at that time: a true writing system. It was a writing system s0 complicated that, so far, no one has been able to interpret it(complete).The fact that Maya society was technologically primitive makes its achievements more incredible and mysterious. Meanwhile, the rise and fall of this civilisation must also leave us(think) about our past, present and future. By 700 AD, Maya cillisation was at (it) peak. Yet, within a couple of generations, it began to mysteriously decline. The cities were left.(take) back by the jungle.Some research seems to indicate that the Maya people themselves may have played a part in their downfall. Research also suggests thatthose natural(disaster) may have led to the decline of the Maya.the reasons, Maya civilisation largely disappeared within the deep jungle.。
关于mysteries的英语作文Title: The Enigma of Mysteries.In the vast expanse of human existence, mysteries have always been an integral part of our lives. They are the unknown forces, the unexplained phenomena, and theenigmatic secrets that captivate our imaginations andprompt us to delve deeper into the recesses of the unknown. Mysteries have existed throughout history, across cultures, and in every sphere of human endeavour. They are as old as civilization itself and continue to fascinate us even inthe age of advanced technology and scientific understanding.The allure of mysteries lies in their nature of being both intriguing and perplexing. They are the puzzles that challenge our intellectual capabilities and push the boundaries of our understanding. They are the voids in the fabric of reality that beg for explanation, yet oftenremain enigmatic even in the face of the most diligent investigation.One of the oldest and most enduring mysteries is the question of the origin of life itself. How did the complex machinery of life emerge from the primordial soup of chemicals? How did the first cells come to be, and how did they evolve into the diverse array of organisms we see today? This mystery is compounded by the equally enigmatic question of consciousness how does the brain, a collection of neurons and synapses, give rise to the subjective experience of being alive?Another enduring mystery is the question of the universe's origin and ultimate fate. How did the universe begin with a cataclysmic event known as the Big Bang, and what lies beyond its expanding boundaries? What is the nature of dark matter and dark energy, the mysterious forces that seem to shape the universe's destiny? And what will become of the universe in the distant future will it continue to expand indefinitely, or will it collapse in upon itself in a cataclysmic end?Mysteries also abound in the realm of human history andculture. The ancient civilizations of Egypt, Mesopotamia, and Peru, with their monumental temples and intricate hieroglyphics, are repositories of secrets that have perplexed scholars for centuries. The lost cities of Atlantis and Mu, and the enigmatic legends of El Dorado and the Fountain of Youth, continue to captivate the imaginations of adventurers and explorers.The human mind itself is a mystery. How does the brain process information, store memories, and generate thoughts and emotions? Why do we dream, and what do our dreams reveal about the inner workings of the mind? The study of neuroscience and psychology has yielded valuable insights into these questions, but the mysteries of the mind remain as elusive as ever.In the realm of science, there are mysteries that challenge our understanding of the fundamental laws of nature. Quantum mechanics, with its paradoxical nature and counterintuitive predictions, has been described as the "mystery of mysteries" by some physicists. The enigmatic properties of quantum particles, such as superposition andentanglement, have defied our classical understanding of reality and continue to baffle even the most seasoned scientists.The enduring appeal of mysteries lies in theirpotential to reveal deeper truths about the universe and ourselves. They are the gaps in our knowledge that drive us to explore, to question, and to seek answers. They are the engines of scientific inquiry and human progress. And while some mysteries may never be fully resolved, the pursuit of knowledge and understanding remains an essential part of our human nature.In conclusion, mysteries are an integral part of human existence, and their enigma continues to captivate us. They challenge our understanding, prompt us to inquire, and drive us to explore. As we delve deeper into the recesses of the unknown, we not only gain new insights into the universe and ourselves, but we also honour the enduring spirit of curiosity and wonder that is unique to the human species.。
北师大版英语高一上学期期中复习试卷及解答参考一、听力第一节(本大题有5小题,每小题1.5分,共7.5分)1、What are the speakers mainly discussing?A. The weather forecast for the weekend.B. The importance of wearing a coat in cold weather.C. How to stay warm during the winter season.Answer: AExplanation: The conversation starts with one speaker mentioning the cold weather forecast for the weekend, indicating that the topic of discussion is the weather.2、How does the woman feel about the movie she just watched?A. She enjoyed it very much.B. She found it too predictable.C. She thought it was not as good as expected.Answer: BExplanation: The woman expresses her disappointment with the movie, stating that it was predictable, which implies that she did not enjoy it as much as she had hoped.3、You hear a conversation between two students discussing their weekend plans.A)They are planning to go hiking.B)They are planning to go shopping.C)They are planning to go to a concert.Answer: BExplanation: The conversation indicates that they will go shopping this weekend, as one student mentions, “I’m going to the mall this weekend.”4、You hear a news report about a new scientific discovery.A)The discovery is about a new type of plant.B)The discovery is about a new animal species.C)The discovery is about a new medical treatment.Answer: CExplanation: The news report specifically mentions that the discovery is related to a new medical treatment, which is being tested in clinical trials.5、You will hear a short conversation between two students, Tom and Lucy. Listen carefully and answer the following question.What is the price of the book Tom wants to buy?A)$10B)$20C)$30D)$40Answer: B)$20Explanation: In the conversation, Lucy asks Tom if he needs any help. Tom responds, “Yeah, I need to buy this book, and it costs$20.” Therefore, thecorrect answer is B)$20.二、听力第二节(本大题有15小题,每小题1.5分,共22.5分)1、What are the speakers mainly discussing?A) The advantages of online learning.B) The challenges of studying abroad.C) The importance of language skills in the job market.Answer: BExplanation: The conversation revolves around the challenges that the speakers are facing due to the high cost of studying abroad, indicating that they are discussing the challenges of studying abroad, not the advantages of online learning or the importance of language skills in the job market.2、Why does the man mention the need for a laptop?A) Because it’s a requirement for the new course.B) Because he needs it for his online classes.C) Because he’s planning to travel soon.Answer: BExplanation: In the conversation, the man specifically mentions the need for a laptop because he will be taking online classes, which suggests that the reason for the laptop is directly related to his studies, not a new course requirement or an upcoming trip.3、You will hear a conversation between two students discussing their weekendplans. Listen to the conversation and answer the question.What does the student suggest they do on Saturday afternoon?A. Go to the movies.B. Visit a museum.C. Go hiking.Answer: BExplanation: In the conversation, one student mentions, “I was thinking we could visit the art museum on Saturday afternoon,” which indicates that visiting a museum is the suggested activity.4、You will hear a short passage about the importance of exercise. Listen to the passage and answer the question.What is the main reason given for exercising regularly?A. To improve physical appearance.B. To reduce stress levels.C. To enhance academic performance.Answer: BExplanation: The passage emphasizes the benefits of regular exercise, particularly in reducing stress and improving overall well-being. The speaker mentions, “Exercise is a great way to reduce stress and improve mental health,” which aligns with option B.5.You are listening to a conversation between two students, Alex and Emily, discussing their weekend plans.Alex: Hey Emily, are you going anywhere this weekend?Emily: Yeah, I’m planning to go hiking in the mountains. How about you, Alex?A lex: That sounds fun! I think I’ll just stay in the city and visit the museum. Emily: Oh, that’s cool. What are you most excited about seeing there? Alex: The new art exhibit. I’ve heard it’s really impressive.Emily: I bet it is. I hope you enjoy your visit. Maybe we can meet up on Sunday afternoon?Question: What is Alex planning to do this weekend?A) Go hiking.B) Visit the mountains.C) Stay in the city and visit the museum.D) Go to the art exhibit.Answer: C) Stay in the city and visit the museum.Ex planation: In the conversation, Alex says, “I think I’ll just stay in the city and visit the museum,” indicating his plan for the weekend.6.You are listening to a news report about a local community event.News Anchor: And now, let’s go to our community r eporter, Sarah, who is at the City Park for the annual Earth Day Festival.Sarah: Good afternoon, everyone. The City Park is bustling with activity as thousands of people have gathered for the Earth Day Festival. The event kicked off with a parade of eco-friendly vehicles and ended with a tree planting ceremony. There are also several workshops and booths offering information onsustainable living and environmental conservation. I spoke with some of the attendees who shared their thoughts on the importance of Earth Day.Attendee 1: It’s so important to raise awareness about the en vironment.I brought my whole family today.Attendee 2: I think events like this really inspire people to make small changes in their daily lives.Sarah: Definitely. It’s great to see so many people coming together for a cause they care about.Question: What is the main purpose of the Earth Day Festival?A) To promote tourism in the city.B) To celebrate Earth Day and raise awareness about environmental issues.C) To provide entertainment for the local community.D) To promote local businesses.Answer: B) To celebrate Earth Day and raise awareness about environmental issues.Explanation: The news report clearly states that the Earth Day Festival is an event to celebrate Earth Day and raise awareness about environmental issues, as mentioned by the news anchor and the attendees.7.You’re listening to a conversation between two students discussing their weekend plans.A. What did the man do last weekend?B. What does the woman plan to do this weekend?C. Why does the woman need to study more?D. How does the woman feel about the upcoming test?Answer: BExplanation: The woman says, “I’m planning to go hiking this weekend,” which indicates her plans for the weekend. The other options are not supported by the dialogue.8.Listen to a short dialogue between a teacher and a student about a missing book.A. What happened to the book?B. Where did the student leave the book?C. Why doesn’t the student have the book?D. How does the teacher respond to the student’s explanation?Answer: CExplanation: Th e student explains, “I’m sorry, I lost it,” which is why they do not have the book. The other options are not mentioned in the dialogue, and the teacher’s response does not confirm the location of the book or the exact situation.9.You hear:W: I heard you’re planning a trip to Beijing this summer. Are you excited? M: Yeah, I can’t wait. I’ve always wanted to visit the Great Wall.Question: What is the man planning to do this summer?A) Visit the Great WallB) Go on a tripC) Travel to ChinaD) Learn ChineseAnswer: A) Visit the Great WallExplanation: The man explicitly states, “I’ve always wanted to visit the Great Wall,” which indicates his plan for the summer is to visit the Great Wall in Beijing.10.You hear:W: I’m thinking of studying abroad, but I’m not sure which country would be best for me.M: Well, if you’re interested in technology and innovation, you should consider going to the United States. They have some of the best universities in the world.Question: What advice does the man give to the woman?A) To study in ChinaB) To focus on technology and innovationC) To choose a country with the best universitiesD) To go to the United StatesAnswer: D) To go to the United StatesExplanation: The man suggests that the woman should consider going to the United States because it has “some of the best universities in the world,” which is related to her interest in technology and innovation.11.You will hear a conversation between two students discussing theirweekend plans. Listen and answer the question.What are the students planning to do on Saturday afternoon?A. Go shopping.B. Visit a museum.C. Have a picnic.Answer: BExplanation: In the conversation, the student mentions that they are planning to visit the local museum on Saturday afternoon. Therefore, the correct answer is B.12.You will hear a short dialogue between a teacher and a student about a homework assignment. Listen and answer the question.What subject is the homework assignment for?A. Math.B. Science.C. History.Answer: AExplanation: The student asks the teacher about the homework assignment, and the teacher responds by saying, “It’s for your math class.” This indicates that the homework is for mathematics, making the correct answer A.13.You will hear a short conversation between two students discussing their plans for the weekend. Listen carefully and choose the best answer to the question.Question: What are the students planning to do this weekend?A. Go to a movie.B. Visit a museum.C. Go hiking.D. Stay home and relax.Answer: B. Visit a museum.Explanation: In the conversation, the students discuss visiting the art museum as their plan for this weekend.14.You will hear a news report about a recent environmental project in the city. Listen carefully and answer the question.Question: What is the main goal of the environmental project?A. To reduce air pollution.B. To plant more trees in the city.C. To promote recycling.D. To create more public parks.Answer: B. To plant more trees in the city.Explanation: The news report mentions that the main goal of the project is to plant more trees in the city to improve the environment and reduce air pollution.15.A) 4B) 5C) 6D) 7Answer: B) 5Explanation: In this question, you need to listen for the specific number mentioned in the dialogue. The correct answer is 5, as it is clearly stated by one of the speakers. The other options are either not mentioned or are incorrect numbers related to the topic.三、阅读第一节(第1题7.5分,其余每题10分,总37.5分)第一题Reading PassageOn a cold November morning in 1922, British archaeologist Howard Carter stood in front of the sealed door of a small, unassuming tomb in the Valley of the Kings in Egypt. Little did he know that behind this door lay one of the greatest mysteries of ancient Egypt: the resting place of the legendary Pharaoh Tutankhamun. For over 3,000 years, Tutankhamun’s tomb had been hidden from the world, preserved in perfect condition by the sands of time.The discovery of Tutankhamun’s tomb was a turning point in the stu dy of ancient Egypt. Carter’s meticulous excavation revealed an astonishing wealth of artifacts, including furniture, jewelry, and the pharaoh’s own tomb. The most famous find, however, was the golden sarcophagus containing Tutankhamun’s mummy. This remarkable discovery provided invaluable insights into the life and times of ancient Egypt.1、Why did Howard Carter stand in front of the sealed door of a small tomb in the Valley of the Kings?A. He was searching for a new source of revenue.B. He had received a tip about the existence of a hidden tomb.C. He was conducting a routine archaeological survey.D. He was looking for a new challenge in his career.2、What did the discovery of Tutankhamun’s tomb mean for the study of ancient Egypt?A. It provided a new source of income for Egyptologists.B. It led to the development of new archaeological techniques.C. It allowed historians to better understand the life and times of ancient Egyptians.D. It sparked a renewed interest in the study of ancient Egypt.3、What was the most famous find in Tutankhamun’s tomb?A. The pharaoh’s chariot.B. The golden sarcophagus.C. The tomb’s entrance.D. The pharaoh’s mummy.4、What did the discovery of Tutankhamun’s tomb provide to historians?A. A new source of revenue.B. A better understanding of ancient Egyptian culture.C. A new source of inspiration for writers.D. A new perspective on the ancient Egyptian civilization.Answers:1、B2、C3、B4、B第二题Read the following passage and answer the questions that follow.In the small town of Willow Creek, there was a tradition that every autumn, the townspeople would gather to celebrate the Harvest Festival. This festival was not just a time for joy and festivities; it was also a way to honor the hard work of the farmers and to give thanks for the bountiful harvest.The festival began with a parade through the town, led by the mayor and the local school children, dressed in colorful costumes. The parade was followed by a variety of activities, including a pumpkin carving contest, a pie eating contest, and a traditional folk music performance.One of the highlights of the festival was the Harvest Market, where local farmers sold their fresh produce, homemade jams, and baked goods. The market was a bustling place, with people of all ages coming to buy and sell.1、What is the main purpose of the Harvest Festival in Willow Creek?A. To celebrate the fall season.B. To honor the farmers and give thanks for the harvest.C. To promote tourism in the town.D. To educate children about history.2、Who leads the parade during the Harvest Festival?A. The town’s firefighters.B. The mayor and the local school children.C. The town’s police officers.D. The local chefs.3、What is one of the activities that takes place during the Harvest Festival?A. A basketball tournament.B. A fishing competition.C. A pumpkin carving contest.D. A talent show.4、What is the Harvest Market known for?A. It is a place to buy and sell antiques.B. It is a place to learn about local wildlife.C. It is a place to purchase fresh produce and homemade goods.D. It is a place to watch traditional dances.Answers:1、B. To honor the farmers and give thanks for the harvest.2、B. The mayor and the local school children.3、C. A pumpkin carving contest.4、C. It is a place to purchase fresh produce and homemade goods.Section III. ReadingPassage:Title: The Power of ReadingReading has been a source of knowledge, inspiration, and entertainment for countless generations. It is a bridge that connects us to the past, a window that opens up new worlds, and a mirror that reflects our own thoughts and emotions. In today’s fast-paced world, where technology dominates every aspect of our lives, the importance of reading cannot be overstated.For students, especially those in high school, reading goes beyond the pages of textbooks. It fosters critical thinking, enhances vocabulary, and improves writing skills. The act of delving into a good book can be a transformative experience, taking readers on a journey of self-discovery and personal growth.Moreover, reading is a form of escape. It allows us to step away from the stresses and pressures of daily life and immerse ourselves in another reality. Whether it’s the thrill of a mystery novel, the romance of a love story, or the wisdom of a philosophical text, books offer a diverse range of emotions and perspectives.The benefits of reading extend beyond the individual. It is a powerful tool for building empathy and understanding across cultures and societies. By reading about different people, places, and experiences, we broaden our horizons and become more tolerant and accepting of diversity.In conclusion, the power of reading is undeniable. It is a fundamental partof our education, a source of personal growth, and a means of connecting with others. Let us embrace the joy of reading and continue to nourish our minds and souls with the wealth of knowledge and inspiration it offers.Third Question: Reading Comprehension1.What is the main idea of the passage?Answer: The power and importance of reading.2.How does reading contribute to students’ development?Answer: Reading fosters critical thinking, enhances vocabulary, and improves writing skills in students.3.What does the author mean when they say “reading is a form of escape”? Answer: The author means that reading allows us to step away from daily stresses and immerse ourselves in another reality, providing a sense of escape.4.What are some of the broader benefits of reading mentioned in the passage? Answer: Some of the broader benefits of reading mentioned in the passage include building empathy and understanding across cultures and societies, broadening horizons, and becoming more tolerant and accepting of diversity.第四题Reading Comprehension (Section A)Read the following passage and answer the questions that follow. Choose the best answer from the options given.Passage:The Great Wall of China, one of the greatest wonders of the world, was listed as a World Heritage by UNESCO in 1987. Just like a gigantic dragon, the GreatWall winds up and down across deserts, grasslands, mountains, and plateaus, stretching approximately 21,196 kilometers from east to west of China. With a history of more than 2000 years, some parts of the Great Wall are now in ruins or have disappeared. However, it is still one of the most appealing attractions all around the world owing to its historical significance.Originally built in different periods by various states to defend their borders against invasions, the Great Wall was later connected and fortified during the Ming Dynasty (1368-1644) to form a comprehensive defense system. The construction of the wall involved millions of workers and took over 2,000 years to complete. It is not only a symbol of the Chinese nation but also a representation of the wisdom and tenacity of ancient Chinese people. Today, the Great Wall serves as a reminder of the past and a source of inspiration for future generations, attracting millions of visitors each year who come to marvel at its grandeur and learn about its rich history.1.What is the total length of the Great Wall of China as mentioned in the passage?•A) 21,196 meters•B) 21,196 kilometers•C) 21,196 feet•D) 21,196 milesAnswer: B) 21,196 kilometers2.In which year did the Great Wall of China get listed as a World Heritage by UNESCO?•A) 1985•B) 1987•C) 1990•D) 1995Answer: B) 19873.During which dynasty was the Great Wall significantly connected and fortified to forma comprehensive defense system?•A) Tang Dynasty•B) Song Dynasty•C) Yuan Dynasty•D) Ming DynastyAnswer: D) Ming Dynasty4.Which of the following statements is NOT true according to the passage?•A) The Great Wall was built to protect the borders from invaders.•B) Some sections of the Great Wall are in ruins or have vanished.•C) The construction of the Great Wall spanned over 2,000 years.•D) The Great Wall no longer attracts tourists due to its deteriorated state.Answer: D) The Great Wall no longer attracts tourists due to itsdeteriorated state.四、阅读第二节(12.5分)Reading SectionPassage:The Great Wall of China is one of the most remarkable architectural wondersin the world. Stretching over 13,000 miles, it was built over several centuries by various dynasties to protect the Chinese empire from invasions. The Wall is a symbol of China’s strength and resilience, and it has become an iconic representation of the country.Today, the Great Wall is a popular tourist destination, attracting millions of visitors each year. It’s not just the length and height of the Wall that fascinates tourists, but also the intricate carvings and the diverse landscapes it traverses. The Wall winds through mountains, deserts, and grasslands, offering a unique blend of natural beauty and historical significance.One of the most famous sections of the Wall is the Mutianyu section, located in the western part of Beijing. This section is known for its well-preserved structures and stunning views. It was built in the 6th century and has been restored several times over the years.Question:What is the primary reason for the construction of the Great Wall of China?A. To provide a scenic view for tourists.B. To attract foreign investors to China.C. To protect the Chinese empire from invasions.D. To promote tourism in China.Answer: C. To protect the Chinese empire from invasions.五、语言运用第一节 _ 完形填空(15分)Title: A Journey of Self-DiscoveryAs a freshman in high school, I found myself standing at a crossroads, unsure of the path ahead. The first semester was filled with excitement and anxiety in equal measure. Every day seemed like a new adventure, yet the pressure to excel academically and socially weighed heavily on my shoulders. It was during this time that I embarked on a journey of 1 discovery, a journey that taught me invaluable lessons about myself.One of the most significant challenges I faced was 2 with my peers. Coming from a different background, I felt like an outsider at times. I struggled to find common ground and feared being judged for my differences. However, through participating in various extracurricular activities and opening up to my classmates, I gradually learned to 3 the beauty in diversity and embrace my uniqueness.Another turning point came when I was assigned to a difficult math course. Math had always been a 4 subject for me, and the thought of struggling through it filled me with dread. But instead of giving up, I decided to face my fears head-on. With the help of my teacher and countless hours of 5, I managed to not only pass the course but also develop a deeper appreciation for the subject. This experience taught me resilience and the importance of perseverance.Moreover, the semester brought about a renewed sense of 6towards learning. As I delved deeper into my studies, I discovered a passion for literature thatI never knew existed. Reading books from diverse cultures and time periods broadened my horizons and sparked a curiosity within me. I realized that education was not just about acquiring knowledge but also about fostering a lifelong love for learning.Through these experiences, I came to understand that life is full of 7 and uncertainties. But it is precisely these challenges that shape us into the individuals we become. I learned to embrace the unknown, to have courage in the face of adversity, and to cherish every moment of growth and self-discovery.Cloze Test Questions (with Options and Answer Key)1.A. personalB. culturalC. scientificD. socialAnswer: A2.A. fitting inB. standing outC. keeping upD. breaking awayAnswer: A3.A. recognizeB. createC. ignoreD. reject Answer: A4.A. fascinatingB. challengingC. relaxingD. enjoyable Answer: B5.A. practiceB. leisureC. debateD. research Answer: A6.A. enthusiasmB. skepticismC. boredomD. apathy Answer: A7.A. certaintiesB. opportunitiesC. obstaclesD. routines Answer: CNote: The passage and questions are designed to test students’ understanding of context, vocabulary, and logical reasoning while engaging in a meaningful topic of self-discovery and growth.六、语言运用第二节 _ 语法填空(15分)For the Grammar Fill-in-the-Blanks SectionDirections: Read the following passage. Fill in each blank with a proper word given below. There are ten blanks followed by four choices marked A, B, C and D. Choose the most appropriate answer for each blank.Text:The Arctic is one of the coldest places on Earth. However, it’s also home to a variety of wildlife that has adapted to live in such harsh conditions. Polar bears, ____(1)____ example, have thick fur and a layer of fat to keep them warm. They spend much of their time hunting seals on the ice. In summer, when the ice melts, polar bears often go onto land and may not eat ____(2)____ several months until the sea freezes over again. Another animal that lives here is the arctic fox, which changes its coat color from brown in summer to white in winter ____(3)____ blend into the snow. Sadly, global warming is causing the Arctic ice ____(4)____ (melt), putting these animals’ habitats at risk.The people who live in the Arctic also face many challenges. The Inuit, ____(5)____ traditionally hunt and fish for a living, must now adapt to changing conditions. For centuries, they ____(6)____ (depend) on the predictability ofthe seasons and the migration patterns of animals. Now, however, they find that the ice is too thin for travel ____(7)____ foot or by dog sled, disrupting their way of life. Despite these difficulties, the Inuit remain resilient and continue to preserve their culture and traditions.Scientists warn that if we do not take action soon, the Arctic might change forever, affecting not just the local inhabitants but the entire planet. It’s hoped that by working together, we can protect this unique environment and ensure it ____(8)____ (survive) for future generations.(1)A. for B. with C. as D. by(2)A. to B. for C. at D. in(3)A. to B. so as C. in order to D. for(4)A. melt B. melting C. melted D. to melt(5)A. whom B. whose C. who D. that(6)A. depend B. depended C. have depended D. had depended(7)A. in B. on C. by D. with(8)A. survive B. survived C. will survive D. has survivedNow let’s provide the answers to this exercise.The correct answers for the grammarfill-in-the-blanks exercise are as follows:1.A. for2.B. for3.A. to4.D. to melt5.C. who6.C. have depended7.B. on8.C. will survive七、写作第一节 _ 应用文写作(15分)Section VII. WritingPart A. Application WritingTask: Write a letter to a friend, expressing your excitement about a recent event you both attended. Include details about the event, your personal feelings, and a suggestion for a future activity.Example:Dear [Friend’s Na me],I hope this letter finds you well! I just wanted to share with you my excitement about the concert we both attended last weekend. It was absolutely fantastic!The venue was beautiful, with a stunning view of the city skyline. The artist, [Artist’s Name], performed live, and the music was simply amazing. The crowd was lively and energetic, and I couldn’t help but feel a sense of joy and unity throughout the evening.I was particularly impressed by [specific part of the concert, e.g., the artist’s performance of a particular song]. The passion and energy he brought to the stage were truly inspiring. It was a night to remember, and I’m so gladwe were able to experience it together.Now, I have a suggestion for our next outing. How about we plan a picnic at the park? We could bring some delicious food, enjoy the beautiful weather, and perhaps even bring along a portable speaker to play some of our favorite music. It would be a great way to relax and spend quality time together.Looking forward to hearing from you soon!Best regards,[Your Name]Analysis:•The letter is well-structured, starting with a greeting and a clear introduction to the topic.•The writer expresses excitement and shares personal feelings about the concert, making the letter more engaging.•Specific details about the concert are provided, such as the venue, the artist, and the crowd, which helps to paint a picture for the reader.• A suggestion for a fu ture activity is offered, showing the writer’s thoughtfulness and desire to continue enjoying time together.•The conclusion is friendly and inviting, encouraging the friend to respond.八、写作第二节 _ 读后续写(25分)Title: “A Surprise Encounter in the Library”。
神秘国度的英语The Mysterious CountryIn a remote corner of the world lies a land shrouded in enigma and wonder. This is the Mysterious Country, a place where the boundaries between reality and fantasy blur, and the impossible becomes tangible. Its very existence is a testament to the boundless imagination of humankind, a realm where dreams and possibilities converge to create a tapestry of the extraordinary.As one ventures into this enigmatic domain, the senses are immediately overwhelmed by the sheer magnitude of the unfamiliar. The landscape is a kaleidoscope of contradictions, where towering mountains of gleaming crystal rise from the depths of lush, verdant valleys. Rivers of molten gold wind their way through the terrain, their gentle currents reflecting the ever-changing hues of the sky above.The inhabitants of this mystical land are a diverse and captivating people, each with their own unique customs and traditions. They areguardians of ancient secrets, wielding powers that defy the limits of human understanding. Their language, a melodic symphony of ancient tongues, carries with it the wisdom of generations, whispering tales of a past that seems to flow seamlessly into the present.As one wanders the winding paths of this Mysterious Country, they are confronted with sights and sounds that challenge the very fabric of their reality. Massive, sentient beings roam the land, their movements graceful and their eyes filled with a profound intelligence that seems to peer into the very depths of the soul. Structures of impossible architecture, defying the laws of physics, stand as silent witnesses to the extraordinary capabilities of the Mysterious Country's inhabitants.The air itself is charged with an energy that is both palpable and elusive. It is a force that seems to flow through every living thing, connecting the tangible and the intangible in a dance of perpetual motion. Those who dare to venture into this realm often find themselves overwhelmed by the sheer intensity of this energy, their senses heightened to a degree that transcends the boundaries of the physical world.Yet, for all its wonders, the Mysterious Country is not without its challenges. Beneath the surface of this enchanting land, there lurks adarkness that is as captivating as it is foreboding. Whispers of ancient rivalries and power struggles echo through the corridors of the Mysterious Country's hidden citadels, hinting at a complex tapestry of political intrigue and conflict.Those who seek to unravel the mysteries of this land must be prepared to confront their own preconceptions and biases. For the Mysterious Country is a realm that defies easy categorization, a place where the very nature of reality is constantly being redefined. It is a challenge to the mind and the spirit, a call to embrace the unknown and to expand the boundaries of one's understanding.Yet, for those who are willing to take on this challenge, the rewards are immeasurable. Within the Mysterious Country, one can find a sense of wonder and awe that is unparalleled, a connection to the primal forces that shape the universe itself. It is a place where the impossible becomes possible, where the boundaries of the known world are shattered, and where the human spirit can soar to unimaginable heights.As the sun sets over the Mysterious Country, casting its golden glow across the land, one cannot help but be struck by the sheer majesty of this place. It is a realm that defies description, a tapestry of the extraordinary that weaves together the threads of myth, legend, and the boundless potential of the human imagination. And for thosewho dare to venture into its depths, the Mysterious Country promises a journey of discovery that will forever transform the way they see the world.。
Update on Biosynthesis of ProanthocyanidinsThe Mysteries of Proanthocyanidin Transport and Polymerization1Jian Zhao,Yongzhen Pang,and Richard A.Dixon*Plant Biology Division,Samuel Roberts Noble Foundation,Ardmore,Oklahoma73401Flavonoids,including proanthocyanidins(PAs;also called condensed tannins),play a multitude of roles in plants(Winkel-Shirley,2001).The presence of certain types offlavonoids in crops is associated with desirable and important agronomic traits;therefore,metabolic engineering offlavonoid biosynthesis has attracted considerable interest(Dixon,2005).PAs are oligomers or polymers offlavan-3-ol units and are prominent flavonoid compounds in seed coats(where they be-come oxidized and confer a brownish color to the testa), leaves,fruits,flowers,and bark(Dixon et al.,2005). Characterization of a series of transparent testa(tt)and tannin-deficient seed(tds)mutants from Arabidopsis (Arabidopsis thaliana)has led to an in-depth understand-ing offlavonoid biosynthesis at the molecular level (Shirley et al.,1995;Winkel-Shirley,2001;Abrahams et al.,2002;Lepiniec et al.,2006;Fig.1).These studies clearly suggest that,in addition to structural enzymes and regulatory factors,transport proteins are also es-sential forflavonoid biosynthesis.Ablation of single transporter genes can result in defects inflavonoid and PA production associated with dysfunction of the cen-tral vacuole(Baxter et al.,2005;Marinova et al.,2007a, 2007b).With increasing evidence of such links between biochemistry and cell biology,transport and trafficking of plant secondary metabolites is emerging as an im-portant,but technically challenging,research frontier (Grotewold,2004).In this Update,we briefly review the status of our knowledge concerning PA biosynthesis and assembly,with particular emphasis on the still controversial mechanisms for transport and polymeri-zation of the PA monomers.MODEL SYSTEMS AND THE BASIC PATHWAY FOR PA BIOSYNTHESISArabidopsis has,until recently,been the major model system for molecular studies of PA biosynthesis (Lepiniec et al.,2006).The model legume Medicago truncatula has recently emerged as another useful system,with the ultimate goal of introducing PAs into the foliar tissues of its close relative,the major forage crop alfalfa(Medicago sativa),to protect rumi-nant animals from pasture bloat and enhance rumi-nant nutrition(Xie et al.,2003;Dixon et al.,2005;Pang et al.,2007,2008;Peel et al.,2009;Zhao and Dixon, 2009).PAs in Arabidopsis and M.truncatula consist of the same monomeric building unit,epicatechin,and have similar biological features(Abrahams et al.,2002; Lepiniec et al.,2006;Pang et al.,2007).Epicatechin shares a common biosynthetic pathway with anthocy-anins from Phe to anthocyanidin(Dixon et al.,2005), from which epicatechin is formed by the action of anthocyanidin reductase(ANR;Xie et al.,2003;Fig.1). The Medicago glycosyltransferase UGT72L1catalyzes UDP-Glc-dependent glycosylation of epicatechin to form epicatechin3#-O-glucoside(E3#G;Pang et al., 2008),which is the substrate for a vacuolar multidrug and toxic compound extrusion(MATE)transporter (Zhao and Dixon,2009;Fig.1).M.truncatula MATE1is an ortholog of Arabidopsis TT12,and both proteins transport cyanidin3-O-glucoside(Cy3G),although E3#G is transported with a higher affinity and velocity (Marinova et al.,2007b;Zhao and Dixon,2009). Grapevine(Vitis vinifera),with a recently sequenced genome,has become another model plant for studying PA biosynthesis.Grapevine PAs consist of two major flavan3-ol monomers,catechin and epicatechin.Their seed and skin PAs have average degrees of polymer-ization of around10and30,respectively.Epicatechin, and to a lesser extent epigallocatechin,is the extension unit and catechin the terminal unit in grapevine PAs (Terrier et al.,2009).Characterization of several tran-scription factors that regulate grapevine PA biosyn-thesis has revealed both similar and distinct regulatory mechanisms from those in Arabidopsis and M.trun-catula(Bogs et al.,2007;Deluc et al.,2008;Terrier et al., 2009).Two TT2-like Myb transcription factors, VvMYBPA1and VvMYBPA2,are essential for the expression of PA biosynthetic genes and PA accumu-lation in grapevine hairy roots(Bogs et al.,2007;Terrier et al.,2009).VvMYBPA1,which is mainly expressed during seed development,specifically regulates PA biosynthetic genes such as ANR and LEUCOANTHO-CYANIDIN REDUCTASE.It can complement the seed PA-deficient phenotype of the Arabidopsis tt2mutant,1This work was supported by the Samuel Roberts Noble Foun-dation and by grants to R.A.D.from Forage Genetics International and the U.S.National Institute of Food and Agriculture(grant no. 2010–65115–20373).*Corresponding author;e-mail radixon@.The author responsible for distribution of materials integral to the findings presented in this article in accordance with the policy described in the Instructions for Authors()is: Richard A.Dixon(radixon@)./cgi/doi/10.1104/pp.110.155432suggesting that VvMYBPA1is an ortholog of TT2,although it is not clear whether grapevine also pos-sesses a TT2-TT8-TTG1-like ternary transcription com-plex such as controls PA biosynthesis in Arabidopsis (Lepiniec et al.,2006;Bogs et al.,2007).VvMYBPA2is mainly expressed in berries and leaves,but constitutive expression of either VvMYBPA1or VvMYBPA2in hairy roots induces similar sets of genes (Terrier et al.,2009).A new player in PA biosynthesis,VvMYB5(Deluc et al.,2008),was also found to regulate the biosynthesis of PAs and other flavonoids in grapevine,and other MYB transcription factors,DkMYB4and PtMYB134,regulate PA biosynthesis in persimmon (Diospyros kaki )fruit and poplar (Populus spp.)leaves,respectively (Akagi et al.,2009;Mellway et al.,2009).These data suggest that MYB family transcription factors are common regula-tors of PA biosynthesis in different tissues.GLUCOSYLATION OF EPICATECHINSeveral studies show that PAs are stored in the vacuoles of Arabidopsis seed coat endothelial cells during the early stages of seed development (Abrahams et al.,2003;Kitamura et al.,2004),and it is likely,but not yet definitively proven,that PA oligomerization/polymerization occurs in the vacuole.As biosynthesis of PA precursors is believed to occur on the cytosolic face of the endoplasmic reticulum (ER)surface,the PA starter and extension units must first be transported into the vacuole.The tt12mutation was mapped toa MATE family transporter (Debeaujon et al.,2001),and TT12protein was shown to localize to the vacuolar membrane.Yeast-expressed TT12could transport Cy3G but not catechin 3-O -glucoside,which could inhibit Cy3G uptake (Marinova et al.,2007b).This was perhaps the first comprehensive characteri-zation of a plant secondary metabolite transporter,incorporating tissue-specific expression,subcellular localization,transport activity,and metabolite profil-ing of loss-of-function lines.However,Cy3G is not considered to be a PA parative studies of MATE1and TT12revealed that the kinetically preferred substrate for both transporters is E3#G rather than Cy3G,which explains the seed phenotypes of the tt12and mate1mutants (Marinova et al.,2007b;Zhao and Dixon,2009).The MATE transporter (CAO69962)from grapevine may carry out similar functions that remain to be determined experimentally (Terrier et al.,2009).If E3#G is universally the vacuolar transport form of epicatechin,its subsequent fate inside the vacuole is still not clear.E3#G can be detected during the early stages of seed development in M.truncatula (Pang et al.,2008),but its levels decrease to zero as PA levels increase,suggesting that it undergoes hydrolysis and subsequent incorporation into the PA polymer.How-ever,other interpretations of the data are possible.For example,glucosylation by UGT72L1could function in part as a detoxification mechanism to “mop up”excess epicatechin,consistent with the fact that this enzyme shows considerably higher sequence similaritytoFigure 1.Genetically mapped TT genes involved in PA biosynthesis in Arabidopsis.tt mutants and their encoding enzymes are as follows:tt4,chalcone synthase;tt5,chalcone isomerase;tt6,flavanone 3-hydroxylase;tt7,flavonoid 3#hydroxylase;tt3,dihydroflavonol 4-reductase;ban ,ANR;tt18(at the same locus as tt11),leucocyanidin dioxygenase;tt10,laccase-like polyphenol oxidase;tt12,MATE antiporter;tt15,UDP-Glc:sterol glycosyltransferase;tt19(at the same locus as tt14),GST;aha10,P-type H +-ATPase.tt mutants encoding regulatory proteins are as follows:tt1,WIK-type zinc finger transcription factor;ttg1(for transparent testa glabra1),WD40repeat transcription factor;tt2,R2R3Myb tran-scription factor;tt8,basic helix-loop-helix tran-scription factor;tt16,MADS domain transcription factor.Zhao et al.multifunctional UGTs,ascribed roles in xenobiotic detoxification,than to otherflavonoid-specific UGTs (Pang et al.,2008).Alternatively,glucosylation of epicatechin could be an integral part of the PA poly-merization mechanism as well as essential for mono-mer transport.In this respect,it is important to note that the exact nature of the starter and extension units of PAs remains to be determined.Gain-and loss-of-function experiments with UGT72L1could give valu-able information about its in vivo function.THE ROLE OF TT19TT19,a glutathione S-transferase(GST),is an essen-tial protein for anthocyanin and PA accumulation in Arabidopsis and has orthologs in other plants such as maize(Zea mays),petunia(Petunia hybrida),and grape-vine(Marrs et al.,1995;Alfenito et al.,1998;Kitamura et al.,2004).GST is believed to function inflavonoid production through its binding toflavonoids rather than by catalyzing the conjugation of glutathione to anthocyanins(Mueller et al.,2000).GST may act as an anthocyanin-binding matrix to protect anthocyanins from oxidation,or the GST-flavonoid complex may facilitateflavonoid transport mediated either by mem-brane transporters(Smith et al.,2003)or via vesicle trafficking.However,the exact mechanisms underly-ing such processes are not understood.The tissue expression patterns of GSTs may provide additional clues to their functions inflavonoid trans-port.TT19is expressed in leaves(particularly during senescence),stems,and young siliques(Kitamura et al.,2004).A TT19promoter::GUS transgene directed high GUS activity to vascular tissues in the mid vein of Arabidopsis leaves,and aflavonoid glycosyltransfer-ase gene exhibits a similar expression pattern(Wenzel et al.,2008).These data suggest that TT19may be involved in long-distance transport offlavonoid-GST complexes(Fig.2)in addition to its proposed role in anthocyanin and PA production in the seed coat, consistent with the lack of pigmentation in leaves and stems of tt19plants(Kitamura et al.,2004).Studies onflavonoid-auxin transport interactions in vegetative axillary bud branching also support this hypothesis (Lazar and Goodman,2006),and long-distance trans-port offlavonoids between cells or organs(e.g.roots and shoots)has recently been demonstrated(Buer et al.,2007).A Medicago GST gene is up-regulated by ectopic expression of either the Medicago Legume Anthocya-nin Production1MYB transcription factor(which con-trols anthocyanin biosynthesis)or the Arabidopsis TT2 MYB transcription factor(which controls PA biosyn-thesis;Pang et al.,2008;Peel et al.,2009).The Medicago GST gene is expressed in vegetative buds,petioles, stems,leaves,andflower tissues.Interestingly,a Medicago anthocyanin transporter,MtMATE2,shows a similar tissue-specific expression pattern to that of the GST,particularly around vascular bundles in petals(J.Zhao and R.A.Dixon,unpublished data). Therefore,both a GST and MtMATE2may be involved in long-distance transport of anthocyanins.It is possi-ble that transported anthocyanins could ultimately serve as precursors of PAs through deglycosylation and subsequent conversion to epicatechin,thus pro-viding an alternative explanation for the reduced PA phenotype of the tt19mutation.THE ROLE OF THE AHA10PROTON PUMPAHA10is a putative P-type H+-ATPase,and Arabi-dopsis aha10seeds show a typical tt phenotype with drastic reduction of PA levels(Baxter et al.,2005).It is not surprising that an H+-ATPase is involved in seed coat PA production,since one would be predicted to be necessary to support the activities of the TT12and MATE1H+antiporters in the Arabidopsis and Medi-cago seed coats,respectively.Both tt12and aha10 mutants show vacuolar morphological defects,consis-tent with the hypothesis that AHA10may be tonoplast localized and provide the H+gradient across the vacuolar membrane to support the MATE trans-porter’s H+/flavonoid antiport function(Baxter et al., 2005).However,it is surprising that tt12seeds do not accumulate epicatechin,whereas aha10seeds contain higher levels of epicatechin than wild-type seeds. One possible explanation for the above paradox is that transporters in addition to TT12may exist for PA transport.If AHA10is located on the tonoplast like its ortholog PH5from petunia(Verweij et al.,2008)and provides an H+gradient for antiporters like TT12, knockout of AHA10may not completely eliminate TT12function because other vacuolar ATPases or vacuolar pyrophosphatases could partially support the E3#G transport function of TT12.Alternatively, AHA10may be localized on the ER or on vesicles involved in PA transport from the cytosol to the vacuole(Fig.2).Vesicle trafficking-mediated PA trans-port may require AHA10to supply energy.Therefore, definitively determining the subcellular localization of AHA10is critical for explaining its biological functions in PA transport.ARE PAS AND THEIR PRECURSORS TRANSPORTED BY VESICLE TRAFFICKING,MEMBRANE TRANSPORTERS,OR BOTH?Early studies suggested that PAs are contained in cytoplasmic vesicle-like structures and that these prevacuole-like vesicles can fuse with the central vac-uole(Abrahams et al.,2002).Vesicle trafficking has also been proposed to be involved in the transport of anthocyanins from the cytosol into the central vacuole (Poustka et al.,2007;Pourcel et al.,2010).Recent studies show that Arabidopsis mutants with reduced PA production exhibit morphological defects in the central vacuole of the seed coat endothelial cells (Abrahams et al.,2003;Kitamura et al.,2004;BaxterProanthocyanidin Transport and Polymerizationet al.,2005);for example,PAs with a patchy,filamen-tous distribution pattern confined to prevacuole-like small vesicles are found in the tt18/tds4mutants (Abrahams et al.,2003;Kitamura et al.,2004;Baxter et al.,2005).Tapetosomes,a unique type of vesicle from tapetum cells of Arabidopsis anthers,contain ER-derived fla-vonoids,oleosins from oil droplets,and alkanes and flavonoids that are released to the pollen surface upon tapetum cell death (Hsieh and Huang,2007).In wild-type Arabidopsis,flavonoids are localized in the ER network and ER-derived tapetosomes but are mostly in the cytosol and not associated with the tapetosome in the tt12and tt19mutants (Hsieh and Huang,2007).This suggests the possibility that TT12and TT19may be involved in the transport of flavonoids into the ER lumen.If so,it is not clear if this is relevant for PA transport.PAs might be carried through ER transportvesicles to the vacuole (Fig.2),and TT12might be on any of the endomembranes involved in such traffick-ing,either in a functional state or as a passenger for the membrane protein targeting pathway,or both.It is generally believed that PAs localize to cell walls in the coats of mature seeds.How epicatechin or PA oligomers are transported out of endothelial cells across the vacuolar and plasma membranes remains unknown.It has been proposed that they are released when the vacuole bursts as a result of cell death during the seed desiccation process (Pourcel et al.,2005).Alternatively,both vesicle trafficking and membrane transporters could be involved in the release of PAs into the apoplast.According to a recent study on the release of callose and antifungal compounds in Arabi-dopsis,both membrane vesicle-mediated (marked with SNARE PEN1syntaxin and SNAP33complex)and membrane transporter-mediated (markedwithFigure 2.Model for PA transport and polymerization.PA regulatory transcription factors (TT factors)activate PA biosynthesis structural genes (TTs)in the nuclei of seed coat endothelial cells under appropriate conditions.PA pathway proteins are translocated to the cytosolic side of the ER for synthesis of epicatechin (white circles)and anthocyanins (red circles).These flavonoids can be compartmentalized in different ways.Epicatechin and anthocyanins are readily glycosylated,and the conjugates are transported into the vacuole by MATE (TT12)transporters.They could also be loaded into the ER membrane system or derived membrane vesicles,which are transported to the central vacuole through prevacuole compartment (PVC)-dependent vesicle trafficking,or else they could be bound to the TT19GST,which facilitates their transport into the ER,vacuole,or other compartments.The acidic vacuolar conditions may facilitate nonenzymatic condensation of PA units,or the units may undergo enzymatic condensation catalyzed by TT10,with E3#G as a possible extension unit,or by yet unidentified proteins (red cylinders).After synthesis on the ER and modification by glycosylation in the Golgi,TT10could be sorted and targeted within membrane vesicles that also contain epicatechin and other PA biosynthetic units.TT10may also catalyze the condensation of PA units into oligomers (such as procyanidin B1and B2)in the vesicles,which are transported to the vacuole,where PA chain elongation could be further catalyzed by TT10using epicatechin glucoside and PA oligomers as substrates.PAs can also be transported through membrane vesicles or other mechanisms to the apoplastic space,where they are subjected to oxidative polymerization and further cross-linked with other cell wall components,catalyzed by apoplastic TT10-like polyphenol oxidases.Blue hexagons represent glycosylated moieties (epicatechin,membrane sterols,and TT10protein).Zhao et al.PDR8/PEN3ATP-binding cassette transporter)secre-tion systems are involved(Meyer et al.,2009).PA oligomers could be transported to the extracellular space by a similar mechanism.The most recently characterized tt gene,tt15,encodes the UDP-Glc:sterol glycosyltransferase UGT8B1(Pourcel et al.,2005;Debolt et al.,2009).In addition to reduced PA levels in seeds,tt15has reduced cyanidin and quercetin levels(Focks et al.,1999),reduced sterol glycoside(SG)and acyl-SG levels in leaf,stem,and silique,and lower suberin and cutin-like polymer levels in the seed coat(Debolt et al.,2009).It is not clear how TT15affectsflavonoid and PA accumulation in seeds.However,it seems likely that the mechanism involves membrane properties,since SG and acyl-SG are important lipid membrane components(Debolt et al.,2009).Proteomic studies showed that UGT8B1is localized to the vacuolar membrane(Carter et al.,2004; Jaquinod et al.,2007).Therefore,loss of function of TT15may indirectly impair vacuolar transporter ac-tivity or vesicle trafficking associated withflavonoid sequestration.It will be of great interest to further pursue these ideas.IS TT10INVOLVED IN INITIALPA OLIGOMERIZATION?Among all characterized tt mutants,tt10is probably the most interesting and mysterious.TT10encodes a putative laccase-like polyphenol oxidase that was proposed to participate in the oxidation and/or po-lymerization of PAs.TT10has a predicted signal peptide for secretion into the apoplastic space,where it has been proposed to oxidize colorless PA oligomers into the oxidized,insoluble,brown PAs characteristic of the mature seed coat(Pourcel et al.,2005).However, several questions remain about the tt10mutant phe-notype.tt10mutant seeds show a clear tt phenotype,which is generally associated with a reduction in the levels of brown,oxidized PAs(Pourcel et al.,2005);the seeds, however,do gradually brown with age.Surprisingly, metabolite profiling shows that tt10seeds have in-creased levels of soluble PAs and someflavonoids but do not have lower levels of oxidized,brown PA products than wild-type seeds(Pourcel et al.,2005). So why do tt10seeds show a tt phenotype without the reduction in PA levels found in other tt mutants?Are there additional oxidized PA products that account for the difference but that cannot be extracted or detected using current techniques?Although TT10has been proposed to catalyze the formation of oxidized PAs linked with cell wall sub-stances to form an insoluble complex in the apoplastic space,studies in which epicatechin was fed to split seeds of tt10and wild-type Arabidopsis indicated that the products of oxidation of free epicatechin by TT10 are nonconventional,“incorrectly linked”PA oligo-mers such as dehydrodiepicatechin A(Pourcel et al.,2005).Thus,if TT10is indeed the initial polymerizing enzyme,either epicatechin is not the natural substrate or additional proteins(perhaps similar to the dirigent proteins involved in dimeric lignan formation;Davin et al.,1997)are necessary and do not function well in the split seed feeding assay.Perhaps the somewhat unusual glycosylation pattern of E3#G is of signifi-cance here.Mostflavonoids with a free3-hydroxyl group on the central C-ring(as found in epicatechin) are glycosylated at this position.Glycosylation at the 3#position would prevent the formation of a B-ring orthodiquinone during oxidation,and this would likely inhibit the formation of B-ring-linked oxidation products such as dehydrodiepicatechin A.It remains to be determined whether E3#G can serve as a sub-strate for TT10to produce a dimer or higher oligomer with the typical C-to A-ring linkage found in natu-ral PAs.Observations on the timing of seed color changes and PA accumulation in the vacuole show that epi-catechin and PAsfirst accumulate in the central vac-uole and then disappear during the later seed desiccation period(Kitamura et al.,2004).However, levels of TT10transcripts temporally parallel those of the PA biosynthetic genes(Pourcel et al.,2005).This seems to be inconsistent with the proposed function of TT10in oxidizing already formed PAs during the late stages of seed maturation(Pourcel et al.,2005),unless the TT10protein has a very long half-life.If TT10only acts as an extracellular enzyme,cata-lyzing oxidative polymerization of epicatechin and PA oligomers in the apoplastic space,the tt10mutation should not affect epicatechin and procyanidin oligo-mers stored intracellularly(i.e.in the vacuole;Kitamura et al.,2004).Unless epicatechin or PA oligomers accu-mulate in the extracellular space from the onset of seed development,the proposed functions of TT10as cur-rently proposed are hard to understand.Better under-standing of the temporal and spatial expression and localization of TT10is clearly required.Does TT10also function as a PA polymerase to catalyze PA chain elongation into higher degree PA oligomers?TT10was excluded as being a PA poly-merizing enzyme mainly on the basis of experiments in which immature tt4-8seeds fed with epicatechin failed to accumulate PAs(Pourcel et al.,2005).How-ever,if epicatechin were not the extension unit,or if TT10catalyzed PA biosynthesis only under specific conditions found within the vacuole,the above feed-ing experiment would not necessarily be informative. If TT10does act as the initial PA-polymerizing enzyme,some of the controversial phenotypes of the tt10mutant could be explained.However,other pos-sible polymerization mechanisms,such as nonenzy-matic polymerization,cannot yet be ruled out(Dixon et al.,2005).These proposed mechanisms are based on an early proposal by Haslam(1977),who showed that acid cleavage of a procyanidin dimer resulted in the formation of an active intermediate(flav-3-en-3-ol) that could then condense with epicatechin to initiateProanthocyanidin Transport and Polymerizationthe formation of higher oligomers.Several models have been proposed whereby such an intermediate could be generated under physiological conditions (Dixon et al.,2005),but these remain theoretical.WHY ARE THERE DIFFERENCES IN PA CONTENT IN SEEDS OF DIFFERENT TT MUTANTS?The differences in levels of epicatechin and PAs in tt mutants compromised in expression of the various structural,regulatory,and transport-related genes are quite dramatic and diverse.Although different ana-lytical methods may account for some of the observed differences(Marles et al.,2003),genetic and biological factors seem more likely.Dissection of such differences between transport-related tt mutants and tt10is of particular interest,since it may provide clues for understanding the complex PA transport and poly-merization processes.One important issue concerns the stability of epi-catechin or PAs in seed endothelium cells.As observed in Arabidopsis,these cells accumulate epicatechin and PAs in the central vacuole,and these do not disappear until the desiccation period of late seed development (Kitamura et al.,2004);thus,epicatechin or PA oligo-mers should be stable inside the vacuole,and vacuolar PA oligomers can be detected in wild-type and tt10 seeds.However,the PA transport-related mutants tt12, tt19,and aha10have an intact biosynthetic pathway but their seeds only have trace levels of PAs,which could perhaps be transported to the vacuole through other pathways or be present elsewhere in the cell.Epicate-chin is present in Arabidopsis developing siliques but is hardly detectable in mature seeds(Abrahams et al., 2002).However,among the tt19,tt12,tt10,and aha10 mutants,only tt10has dramatically increased free epi-catechin levels throughout seed development(Pourcel et al.,2005),suggesting that TT10is directly related to the metabolic fate of epicatechin via PA stability, polymerization,or subsequent catabolism. Determining whether3#-O-glucosylation is essential for stabilizing epicatechin,providing a substrate for TT12,or forming E3#G as an extension unit for PA polymerization is critical for furthering our under-standing of PA biosynthesis.While mature Arabidop-sis seeds(except tt10)do not accumulate detectable levels of free epicatechin and E3#G,young M.trunca-tula seeds contain high levels of both(Marinova et al., 2007b;Pang et al.,2008).M.truncatula UGT72L1is expressed in the seed coat and shows high specificity for E3#G biosynthesis(Pang et al.,2008),but the corresponding Arabidopsis epicatechin glycosyltrans-ferase has yet to be identified.PERSPECTIVESAlthough TT12-and MATE1-mediated sequestra-tion of E3#G into the central vacuole may provide the building unit(s)for PA polymerization,additional mechanisms may exist for the transport of monomers for PA biosynthesis,since tt12,aha10,and tt19all retain low levels of PAs.Furthermore,the PAs of alfalfa, grapevine,and other species consist of both epicate-chin,as extension units,and catechin,as the starter unit,suggesting the possible need for additional trans-porters for catechin or some derivative thereof. Among19tt mutants identified from Arabidopsis, tt9,tt13,and tt17remain to be characterized.These may represent lesions in genes encoding proteins similar to TT15or AHA10,not directly involved in PA biosynthesis but indirectly affecting PA transport or polymerization pathways.Characterization of these mutants,coupled with biochemical analysis of poly-merization mechanisms informed by the nature of the intermediates that are actually transported to the vacuole,may help reveal the remaining mysteries of PA transport and polymerization.Better understand-ing of these processes will ultimately help us to manipulate PA production in crop species.In summary,in spite of the significant progress that has been made in understanding PA biosynthesis and its regulation in the past5years,many questions still remain unanswered,among which are the following. Is TT12only localized to the tonoplast,and do all PA monomers have to directly cross this membrane from the cytosol?If PAs are polymerized in the vacuole, how are they then transported to the extracellular space?How is TT19involved inflavonoid transport? Is it also involved in long-distance transport offlavo-noids,and,if so,does this process impact PA biosyn-thesis?How does AHA10function in PA biosynthesis, and what is its subcellular localization?Does glycosyl-ation of epicatechin only facilitate vacuolar transport, or is it integral for PA polymerization?Is TT10in-volved in the initial polymerization of PAs in addition to oxidation of existing PA oligomers/polymers? What are thefine structures of insoluble PA polymers and naturally occurring colored PA polymers?How can we better quantify them,and do our current methods give a true representation of their composi-tions?Received February24,2010;accepted April9,2010;published April13,2010. 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