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喜欢电子书的英语经历作文Title: The Evolution of My Love for E-books。
Introduction:In this digital age, technology has revolutionized various aspects of our lives, including the way we read books. As an avid reader, I have witnessed the transformation from traditional paperbacks to the rise ofe-books. In this essay, I will share my personal journey and experiences with e-books, highlighting their advantages and the impact they have had on my reading habits.Body:1. Early skepticism and transition:When e-books first emerged, I was initially skeptical about their appeal. The feel of a physical book, the scent of its pages, and the joy of flipping through them seemedirreplaceable. However, as technology advanced and e-readers became more popular, I decided to give e-books a chance. I purchased my first e-reader, and thus began my journey into the world of electronic reading.2. Convenience and accessibility:One of the immediate advantages I discovered with e-books was their convenience. With a single device, I could carry an entire library wherever I went. Whether travelingor commuting, I no longer needed to choose between books to carry along. Additionally, e-books are accessible at any time, eliminating the need to visit bookstores or wait for deliveries. This convenience opened up a world of possibilities for my reading habits.3. Cost-effectiveness and environmental impact:Another significant advantage of e-books is their cost-effectiveness. Compared to physical books, e-books areoften cheaper, especially for popular titles or bestsellers. Additionally, e-books eliminate the need for physicalproduction, reducing paper consumption and theenvironmental impact associated with traditional publishing. This realization further enhanced my appreciation for e-books.4. Customization and reading experience:E-books offer a range of customization options that enhance the reading experience. Font sizes, styles, and background colors can be adjusted to suit personal preferences, making reading more comfortable forindividuals with visual impairments or other reading difficulties. Furthermore, e-books often include features like bookmarks, highlighting, and note-taking, allowing readers to interact with the text and easily revisit important passages.5. Availability and diversity:The digital nature of e-books has significantly expanded the availability and diversity of reading materials. With just a few clicks, I can access a vastcollection of e-books from various genres, authors, and publishers. This has allowed me to explore new genres and discover authors I may not have encountered otherwise. The ease of access has broadened my reading horizons and enriched my literary experiences.6. Enhanced reading experience:E-books have introduced new possibilities for enhancing the reading experience. Features like built-in dictionaries and instant translations have made reading foreignliterature more accessible. Additionally, multimedia elements such as images, videos, and interactive graphics can be included in e-books, providing a more immersive and engaging reading experience. These enhancements have made reading more dynamic and interactive, further deepening my love for e-books.7. Community and social aspects:Contrary to the misconception that e-books isolate readers, digital reading platforms have fostered a sense ofcommunity and social interaction. Online book clubs, forums, and social media groups dedicated to discussing e-bookshave connected me with fellow readers from around the world. Sharing recommendations, participating in virtual book discussions, and receiving real-time feedback has added a social dimension to my reading experience.8. Preservation and archiving:E-books offer a practical solution for preserving and archiving literary works. With physical books, wear andtear over time can lead to deterioration. However, e-books remain intact and can be easily stored and accessed indefinitely. This preservation aspect is particularly valuable for rare or out-of-print books that may otherwise be difficult to find or afford. Knowing that cherished literary works can be preserved for future generations is a comforting thought.Conclusion:In conclusion, my journey with e-books has beentransformative. From initial skepticism to embracing their advantages, e-books have become an integral part of my reading experience. The convenience, accessibility, customization, and enhanced reading experience they offer have broadened my literary horizons and deepened my love for books. As technology continues to evolve, I am excited to see how e-books will continue to shape the future of reading.。
乒乓在中国受欢迎的原因英语作文全文共6篇示例，供读者参考篇1Ping Pong, also known as table tennis, is super duper popular in China because it's so much fun to play!First of all, it's super easy to play ping pong. All you need is a paddle, a ball, and a table. You can play it indoors or outdoors, so you can play it pretty much anytime and anywhere. And the rules are simple too – just hit the ball back and forth over the net. Easy peasy, right?Another reason why ping pong is so popular in China is because it's a great way to stay fit and healthy. You have to move around a lot and use your arms and legs to hit the ball, so it's a great workout. Plus, it's a super fast-paced game, so it's really good for your reflexes and coordination.And let's not forget about the competitive aspect of ping pong. In China, there are so many ping pong champions and tournaments, so people love to watch and play the game to see who's the best. It's really exciting to see all the fast and fancymoves that the players can do – it's like watching magic happen right before your eyes!All in all, ping pong is just a super cool and fun game that's loved by so many people in China. It's easy to play, good for your health, and super competitive. So if you ever get the chance to play ping pong, give it a shot – you'll be hooked in no time!篇2Ping pong, also known as table tennis, is a really popular sport in China. Do you know why? Let me tell you!First of all, ping pong is super fun to play! You just need a table, a ball, and a paddle, and you're ready to go. It's easy to learn but hard to master, so anyone can enjoy playing it, no matter how old they are. And when you hit that perfect shot and the ball zooms past your opponent, it's such a great feeling!Secondly, ping pong is really good for your health. It helps you improve your hand-eye coordination, reflexes, and agility. Plus, it's a great way to get some exercise and stay active. And you can play it indoors or outdoors, so you can enjoy it no matter what the weather is like.Another reason why ping pong is so popular in China is because of the country's strong tradition in the sport. Chinese athletes have been dominating the international ping pong scene for years, winning countless medals in competitions all around the world. This has inspired a whole generation of young players to pick up a paddle and start playing.Lastly, ping pong is a great way to socialize and make friends. You can play it with your family, your friends, or even with strangers at a local ping pong club. It's a fantastic way to bond with others and have some fun together.So there you have it – ping pong is popular in China because it's fun, good for your health, has a strong tradition, and is a great way to socialize. If you ever get the chance, give it a try –you might just fall in love with this awesome sport!篇3Why is table tennis so popular in China? Let me tell you!First of all, table tennis is a national sport in China. Many Chinese people love playing table tennis and even watch competitions on TV. It is like a national treasure and everyone takes pride in their country's success in the sport.Secondly, table tennis is a fun and easy game to play. Unlike other sports that require a lot of physical strength and stamina, table tennis can be played by people of all ages and abilities. It is a great way to stay active and have fun with friends and family.Moreover, table tennis is a strategic game that requires quick thinking and fast reflexes. Players need to anticipate their opponent's moves and react quickly to hit the ball back. This makes the game exciting and challenging for both beginners and experienced players.In addition, Chinese athletes have dominated the sport of table tennis for years. With famous players like Ma Long and Ding Ning winning Olympic medals, many young Chinese people are inspired to take up the sport and dream of representing their country on the world stage.Overall, table tennis has become a beloved pastime in China because of its national pride, accessibility, strategic gameplay, and successful athletes. So if you ever visit China, be sure to challenge a local to a friendly game of ping pong!篇4Title: Why is table tennis so popular in China?Hey guys! Today, I want to talk about why table tennis is so popular in China. Everybody knows that table tennis, or ping pong as we like to call it, is like a national sport in China. People of all ages love to play and watch table tennis matches. So, why is it so popular?First of all, table tennis is a game that anyone can play. You don't need to be super tall or super strong to play table tennis. All you need is a paddle, a ball, and a table. This makes it accessible to almost everyone, which is why so many people in China love to play.Secondly, table tennis is a fast-paced and exciting game. The rallies can be super intense, with players smashing the ball back and forth at lightning speed. It's thrilling to watch, and even more fun to play. Plus, it's a great way to get some exercise and improve your hand-eye coordination.Another reason why table tennis is so popular in China is because of our top players. Chinese table tennis players are some of the best in the world, and they have won countless championships and medals. Seeing our players succeed on the international stage inspires young and old alike to pick up a paddle and start playing.Finally, table tennis has a long history in China. It has been played here for over 100 years, and has become deeply ingrained in our culture. It's not just a sport, it's a part of who we are as a nation.In conclusion, table tennis is popular in China for a variety of reasons, including its accessibility, excitement, top players, and cultural significance. It's a game that brings people together, and we are proud to call it our national sport. So, next time you're in China, make sure to pick up a paddle and join in on the fun!篇5Ping pong, also known as table tennis, is a super popular sport in China. There are so many reasons why we love it so much!First of all, ping pong is super fun to play. You get to hit the ball back and forth across the table with your friends. It's like a mix of tennis and badminton, but on a smaller scale. Plus, you can play it indoors or outdoors, so you can have a great time no matter what the weather is like.Another reason why ping pong is so popular in China is because it's a great way to stay active and healthy. When you play ping pong, you have to move around a lot and use yourhand-eye coordination to hit the ball. It's a great workout without even realizing it!Also, ping pong is super easy to learn. You just need a table, a paddle, and a ball, and you're all set to play. You can learn the basic rules in no time and start having fun right away. It's a sport that anyone can enjoy, no matter how old or young you are.Lastly, ping pong is a big part of Chinese culture. We have produced so many amazing players who have won medals in international competitions. People in China are so proud of our ping pong heritage, and we love to support our athletes in every match they play.In conclusion, ping pong is a super popular sport in China because it's fun, healthy, easy to learn, and a big part of our culture. If you ever get the chance to play ping pong in China, you should definitely give it a try. You won't regret it!篇6In China, ping pong is super popular! Do you know why? Let me tell you all about it!First of all, ping pong is like the national sport in China. Everyone plays it, from kids to adults. You can play at home, atschool, or at a ping pong club. It's so easy to pick up a racket and start playing!Secondly, ping pong is super fun! You get to hit the little ball back and forth with your friends or family. It's a great way to spend time together and have some friendly competition. Plus, you can do all kinds of cool tricks with the ball, like spins and smashes.Another reason why ping pong is so popular in China is because we have some of the best players in the world. Our top players have won so many medals at international competitions. Everyone wants to be as good as them, so they practice really hard and try to improve their skills.Lastly, ping pong is a great way to stay healthy and active. It helps improve your coordination, reflexes, and concentration. Plus, it's a great way to relieve stress and have some fun!So, that's why ping pong is so popular in China. It's a national sport that's fun, competitive, and good for your health. If you ever visit China, make sure to play a game of ping pong with us! It's a blast!。
乒乓球运动的发展英语作文Title: The Development of Table Tennis。
Table tennis, also known as ping pong, has witnessed remarkable growth and evolution since its inception. Fromits humble origins to becoming an Olympic sport, thejourney of table tennis exemplifies the fusion of tradition and modernity in sports. In this essay, we will explore the key milestones and factors contributing to the developmentof table tennis.Firstly, let's delve into the historical roots of table tennis. The origins of table tennis can be traced back to Victorian England in the late 19th century. Initiallyplayed as an after-dinner parlor game among the upper class, it soon gained popularity across social strata due to its accessibility and engaging nature. The early version oftable tennis involved makeshift equipment, such asmakeshift paddles and simple balls, and improvised playing surfaces like dining tables.The modernization of table tennis began in the early20th century, particularly with the establishment of formal rules and regulations. The formation of the International Table Tennis Federation (ITTF) in 1926 marked a significant milestone, providing a platform for standardization and global governance of the sport. With standardized equipment specifications and competition guidelines, table tennis transitioned from a recreational pastime to a competitive sport.Throughout the mid-20th century, table tennis experienced a surge in popularity, especially in Asia. Countries like China, Japan, and South Korea emerged as dominant forces in the sport, showcasing exceptional skill and technique on the international stage. The emergence of iconic players such as Zhuang Zedong, Deng Yaping, and Jan-Ove Waldner further propelled the global appeal of table tennis and inspired generations of enthusiasts.The inclusion of table tennis in the Olympic Games in 1988 marked a watershed moment for the sport, elevating itsstatus to that of a mainstream athletic discipline. Since then, table tennis has been a staple feature of the Olympics, captivating audiences worldwide with its fast-paced rallies and precision gameplay. The Olympic platform not only provides exposure and recognition to top players but also fosters grassroots development and participation in table tennis across diverse demographics.In recent years, technological advancements have revolutionized the landscape of table tennis. Innovations such as high-performance rubbers, carbon-fiber blades, and automated training systems have enhanced the speed, spin, and control of the game. Furthermore, the advent of online platforms and digital coaching resources has democratized access to training and knowledge, empowering enthusiasts to improve their skills and connect with the global table tennis community.Looking ahead, the future of table tennis appears promising, fueled by ongoing efforts to expand its reach and relevance. Initiatives such as Table Tennis for All (TT4ALL) aim to promote inclusivity and diversity withinthe sport, ensuring that table tennis remains accessible to people of all ages, backgrounds, and abilities. Moreover, collaborations between the ITTF and other organizationsseek to innovate and adapt table tennis to evolvingsocietal trends and preferences, thereby sustaining its appeal in the modern era.In conclusion, the development of table tennis embodies a rich tapestry of tradition, innovation, and globalization. From its origins as a leisurely diversion to its status asa global sporting phenomenon, table tennis continues to captivate hearts and minds around the world. Through strategic partnerships, technological advancements, and a commitment to inclusivity, the future of table tennisshines brightly, promising new heights of excellence and enjoyment for generations to come.。
国乒发展作文英语The Development of Chinese Table Tennis。
Table tennis, also known as ping pong, is a popular sport around the world. However, no country has dominated the sport like China has. China has won over 60% of all table tennis world championships since 1959, and has produced some of the greatest players in history. So, how did China become the powerhouse of table tennis?The development of Chinese table tennis can be traced back to the 1950s, when the sport was introduced to China by foreign workers. The Chinese government quickly recognized the potential of the sport and began investing heavily in it. They built training facilities and recruited the best coaches from around the world to train Chinese players.In the 1960s, China began to dominate the sport at the international level. Rong Guotuan became the first Chineseplayer to win a world championship in 1961, and he was followed by Zhuang Zedong, who won three straight world championships from 1961 to 1965. The success of these players inspired a generation of Chinese players, who began to train harder and dream of winning world championships themselves.In the 1970s, China continued to dominate the sport, winning nine of the ten world championships held during the decade. The Chinese players were known for their precision, speed, and agility, and their dominance of the sport was only growing.However, in the 1980s, China faced a new challenge. The International Table Tennis Federation (ITTF) changed the rules of the sport, making the ball larger and slowing down the game. This change was intended to make the sport more exciting for viewers, but it had the unintended consequence of making it more difficult for Chinese players, who were used to playing with smaller and faster balls.Despite this challenge, China continued to produce top-level players, such as Deng Yaping, who won four Olympic gold medals and ten world championships during her career. The Chinese government continued to invest heavily in the sport, building more training facilities and recruiting the best coaches from around the world.Today, China remains the dominant force in table tennis. Chinese players have won every Olympic gold medal in the sport since 2000, and they continue to win the majority of world championships. The success of Chinese table tennis is a testament to the country's commitment to investing in sports and developing world-class athletes.In conclusion, the development of Chinese table tennisis a story of investment, dedication, and hard work. From the early days of the sport in China to the present day,the Chinese government and its people have workedtirelessly to produce the best players in the world. As a result, China has become the undisputed champion of table tennis, and its players continue to inspire future generations of athletes around the world.。
乒乓英语作文The Magic of Ping-PongOrigins and Evolution of Ping-PongPing-pong, a sport that has captivated hearts across the globe, has a rich and fascinating history. Tracing its origins back to the late 19th century, it emerged as a parlor game, a casual pastime enjoyed by friends and family. Over time, however, it transformed into a competitive sport, gaining recognition and popularity worldwide.The simplicity of ping-pong’s rules and equipment has been key to its widespread appeal. All that is needed is a table, paddles, and a ball. These basic requirements have allowed the sport to penetrate into various cultures and communities, becoming a unifying force across borders. The sport’s growth has been exponential, with tournaments and championships being held globally, attracting top-level athletes from diverse backgrounds.The evolution of ping-pong has not only been about competition but also about innovation. The sport has seen advancements in technology, with improvements in equipment such as paddles and balls, enhancing the overall playing experience. These innovations have also led to the development of new techniques and strategies, pushing the boundaries of the sport and challenging players to be better.The unique sound of the ball bouncing on the table, the swiftness ofthe paddles, and the intense rallies create an atmosphere of excitement and anticipation. Whether it’s a casual match between friends or a high-stakes competition at the international level, ping-pong offers a thrilling experience that captivates the audience.Unity and Friendship Through Ping-PongBeyond its competitive nature, ping-pong serves as a powerful tool for fostering unity and friendship. Its inclusive nature allows people of all ages and backgrounds to come together and enjoy the game, breaking down barriers and promoting cultural exchange.On the court, ping-pong players must work together, whether as doubles partners or as competitors in singles matches. They learn to read each other’s cues, anticipate their opponent’s moves, and develop a shared understanding of the game. This process not only enhances their performance but also builds trust and respect among them.Off the court, ping-pong provides an opportunity for people to connect and engage in meaningful conversations. It serves as a common ground for individuals from different cultures and backgrounds to share experiences, learn from each other, and create lasting friendships.The sport has also been a powerful force in promoting international cooperation and understanding. Through tournaments and exchange programs, ping-pong players from around the world have the opportunity to compete against each other, share ideas, and develop a mutual respectfor their differing skills and strategies.Ping-Pong as a Tool for Health and FitnessPing-pong is not just a sport for competition and friendship; it is also an excellent tool for promoting health and fitness. Its low-impact nature makes it suitable for individuals of all fitness levels, offering a great workout while also improving coordination, flexibility, and reaction time.Playing ping-pong requires constant movement and adjustment of the body, engaging various muscle groups and improving overall physical conditioning. The sport’s quick and precise movements help to enhance hand-eye coordination, balance, and spatial awareness. Regular practice can lead to improved flexibility and agility, as well as increased cardiovascular fitness.Moreover, ping-pong can be a fun and effective way to stay active and healthy. It provides a low-intensity workout that can be enjoyed by people of all ages, making it an ideal choice for those looking to incorporate physical activity into their daily routine. The social aspect of the sport also adds to its appeal, as it provides an opportunity to meet new people, make friends, and enjoy a healthy lifestyle together.Conclusion: The Enduring Appeal of Ping-PongPing-pong, with its rich history, competitive spirit, and inclusive nature, has established itself as a timeless sport. Its simplicity and accessibility have made it a global phenomenon, attracting millions ofenthusiasts from all corners of the world.The sport’s ability to bring people together, foster unity and friendship, and promote health and fitness is truly remarkable. It serves as a powerful tool for cultural exchange and understanding, breaking down barriers and creating a sense of community among its players.As ping-pong continues to evolve and grow, it will undoubtedly remain a fixture in the hearts of sports enthusiasts worldwide. Its magic lies in its ability to bring joy, excitement, and a sense of accomplishment to those who play it. Whether it’s a casual game with friends or a competitive match at the international level, ping-pong offers an experience that is truly unique and unforgettable.In conclusion, ping-pong is not just a game; it’s a way of life. It teaches us the importance of teamwork, strategy, perseverance, and the value of physical activity. It brings people together, creates lasting friendships, and promotes a healthy lifestyle. As we continue to embrace the magic of。
介绍乒乓球英语作文Table tennis, also known as ping-pong, is a sport that has captured the hearts of millions around the globe. It is a fast-paced game that requires agility, precision, and strategy. In this essay, we will delve into the history, rules, and significance of table tennis, as well as its impact on sports culture.Origins and Evolution:Table tennis originated in the late 19th century in England as an after-dinner game among the upper-class. It evolved from the parlor game whiff-whaff to the more competitive sport we know today. The name "ping-pong" comes from the sound made by the ball hitting the paddle and table.Basic Rules and Gameplay:The game is played between two or four players (singles or doubles) on a hard table divided by a net. The small, lightweight ball is struck with a small, wooden paddle covered with rubber on both sides. Points are scored when a player fails to return the ball before it bounces twice.Equipment and Techniques:Players use different types of paddles depending on their playing style. The rubber on the paddle can be smooth for a faster speed or textured for more spin. Techniques such as the forehand and backhand strokes, as well as the serve and return, are fundamental to the game.Health Benefits and Popularity:Table tennis is not only a competitive sport but also a great way to improve hand-eye coordination, concentration, and physical fitness. It is popular among people of all ages and is often played recreationally in schools, community centers, and even at home.International Competitions:The sport has a significant presence in international competitions, including the Olympics, where it has been a medal event since 1988. China has dominated the sport, producing many world champions.Cultural Impact:Table tennis has also played a role in international diplomacy, famously known as "ping-pong diplomacy" when the United States and China used the sport to ease political tensions in the 1970s.Conclusion:Table tennis is more than just a sport; it is a cultural phenomenon that brings people together across borders. Its simplicity and universal appeal have made it a beloved pastime and a serious competitive endeavor. Whether you're picking up a paddle for the first time or you're an aspiring champion, table tennis offers a unique blend of fun and challenge that keeps players coming back for more.。
乒乓作为国球吸引人们的原因英语作文全文共3篇示例，供读者参考篇1Table tennis, or ping pong, has become a national sport in China and gained immense popularity all over the world. Its rapid-paced gameplay and exciting competition have attracted people of all ages and backgrounds. There are several reasons why table tennis has become a national favorite and continues to captivate audiences worldwide.First and foremost, table tennis is a sport that is easy to play but difficult to master. The basic rules of the game are simple to understand, and the equipment required is minimal – just a table, paddles, and a ball. This accessibility makes table tennis a popular choice for recreation and competition. Anyone can pick up a paddle and start playing, but to excel at the sport requires skill, strategy, and practice. This combination of simplicity and complexity makes table tennis appealing to players of all skill levels.Another reason for the popularity of table tennis is itsfast-paced and exciting gameplay. Matches can move quickly,with players using lightning-fast reflexes to return shots and score points. The back-and-forth nature of the game keeps spectators on the edge of their seats, as rallies can end in an instant or go on for several minutes. The intensity of the competition and the skill displayed by players make table tennis a thrilling sport to watch.In addition to its gameplay, table tennis has been embraced as a national sport in China, where it is known as the national ball game. Chinese players have dominated the sport on the international stage, winning numerous Olympic medals and World Championships. These successes have helped propel table tennis to the forefront of Chinese sports culture, inspiring generations of players and fans. The popularity of table tennis in China has also had a global impact, as Chinese players have set the standard for excellence in the sport.Furthermore, table tennis has evolved over the years to become more than just a game – it has become a lifestyle. Players around the world participate in table tennis clubs, leagues, and tournaments, where they can hone their skills, compete against others, and socialize with fellow enthusiasts. Table tennis has also become a popular activity for fitness and recreation, as playing the sport can improve hand-eyecoordination, reflexes, and overall physical fitness. The social aspect of table tennis, combined with its physical and mental benefits, has contributed to its widespread appeal.In conclusion, table tennis has become a national favorite and a global phenomenon for several reasons. Its accessibility, fast-paced gameplay, competitive spirit, and social aspects have made it a beloved sport for players and fans alike. Whether you're a casual player looking for fun or a serious competitor seeking glory, table tennis has something to offer everyone. As the national ball game of China and a popular pastime around the world, table tennis continues to captivate audiences and inspire new generations of players.篇2Table tennis, also known as ping pong, is considered the national sport of China. It has become extremely popular not only in China but also around the world. There are several reasons why table tennis attracts so many people.First of all, table tennis is a sport that can be enjoyed by people of all ages and skill levels. Whether you are a beginner playing for fun or an experienced player competing in tournaments, table tennis offers something for everyone. Therules are simple and easy to understand, making it accessible to people of all ages. It is a great way for people to stay active and improve their hand-eye coordination.Secondly, table tennis is a fast-paced and exciting sport to watch. The quick movements, fast serves, and intense rallies make it thrilling for both players and spectators. The skill and strategy involved in the game also add to the excitement. Watching players maneuver the ball with precision and speed can be mesmerizing.Furthermore, table tennis is a sport that promotes social interaction and camaraderie. Whether you are playing doubles with friends or competing in a team tournament, table tennis fosters a sense of community and teamwork. It is a great way to meet new people, make friends, and build relationships. The friendly competition and sportsmanship found in table tennis make it a popular choice for social gatherings and events.In addition, table tennis is a sport that can be played almost anywhere. Whether you have access to a dedicated table tennis facility or simply a small space at home, you can enjoy a game of table tennis. The portability and accessibility of table tennis make it a convenient and popular choice for people looking to stay active and have fun.Overall, the popularity of table tennis as the national sport of China and as a global sport can be attributed to its accessibility, excitement, and social aspects. Whether you are a casual player looking for some fun or a serious competitor aiming for greatness, table tennis has something to offer everyone. So grab a paddle, find a table, and join in on the fun of this beloved sport.篇3Table tennis, also known as ping-pong, has been designated as the national sport of China. It is not only a popular recreational activity but also a highly competitive sport that attracts millions of fans worldwide. The game's fast-paced nature, strategic elements, and accessibility make it an appealing choice for people of all ages. In this essay, we will explore the reasons why table tennis is considered a national sport and what makes it so attractive to people around the world.One of the main reasons why table tennis is so popular is its fast-paced nature. The game requires quick reflexes, agility, and precision, making it an exciting and thrilling sport to watch and play. The rapid back-and-forth exchanges between players keep spectators on the edge of their seats, while players must constantly be on their toes to anticipate their opponent's moves. This fast-paced gameplay not only makes table tennis excitingbut also helps to improve players' hand-eye coordination and reaction time.Another reason why table tennis is so appealing is its strategic elements. Despite its simple rules and equipment, table tennis is a game of skill and strategy. Players must carefully plan their shots, anticipate their opponent's moves, and adapt their tactics on the fly. The ability to read the game, employ different serves, and execute various shots makes table tennis a mentally challenging and rewarding sport. This strategic element adds depth to the game, making it a favorite among competitive players and spectators alike.Furthermore, table tennis is a sport that can be enjoyed by people of all ages and skill levels. Unlike other sports that require expensive equipment or specialized training, table tennis is accessible to almost everyone. All you need is a table, a paddle, and a ball to get started. Whether you are a beginner playing for fun or a seasoned pro competing in tournaments, table tennis offers something for everyone. Its simplicity and versatility make table tennis a sport that can be enjoyed by people of all backgrounds and abilities.In addition to its fast-paced nature, strategic elements, and accessibility, table tennis also has a rich history and culturalsignificance that adds to its appeal. Table tennis has a long and storied history, dating back to the late 19th century in England. Over the years, the sport has evolved and grown in popularity, becoming a national sport in countries like China and a favorite pastime in many parts of the world. Table tennis has also played a role in fostering international relations and cultural exchange, with competitions like the World Table Tennis Championships bringing together players from different countries and backgrounds.In conclusion, table tennis is a sport that has captured the hearts of millions of people around the world. Its fast-paced gameplay, strategic elements, accessibility, and cultural significance make it a popular choice for players and fans alike. Whether you are a casual player looking for some fun or a competitive athlete aiming for glory, table tennis has something to offer everyone. With its thrilling matches, intense rivalries, and exciting tournaments, table tennis will continue to attract people and inspire future generations of players for years to come.。
乒乓球发展启示英语作文Ping pong, also known as table tennis, has a rich history and has provided us with valuable insights and inspirations. Firstly, it teaches us the importance of focus and concentration. When playing ping pong, one must pay close attention to the ball and be fully present in the moment. This skill can be applied to various aspects of life, such as studying, working, or even having a conversation. By staying focused, we can achieve better results and make the most out of our time.Secondly, ping pong promotes quick thinking and decision-making. In a fast-paced game, players need to react swiftly and make split-second decisions on how to return the ball. This ability to think on our feet is crucial in many situations, especially when faced with unexpected challenges or opportunities. Ping pong reminds us of the importance of adapting quickly and making the best decisions under pressure.Furthermore, ping pong encourages perseverance and resilience. It is a sport that requires practice and continuous improvement. Players must be willing to put in the effort and overcome obstacles in order to become better. This lesson can be applied to all areas of life, as success often comes from perseverance and the ability to bounceback from failures. Ping pong teaches us to never give up and to keep pushing forward, even when faced with setbacks.In addition, ping pong fosters teamwork and communication. Doubles matches in ping pong require players to work together and coordinate their movements. Effective communication is essential in order to anticipate eachother's actions and make strategic decisions. This reminds us of the importance of collaboration and effective communication in achieving common goals, whether it be in sports, work, or personal relationships.Lastly, ping pong promotes a healthy and active lifestyle. It is a sport that can be enjoyed by people ofall ages and fitness levels. Playing ping pong regularlycan improve hand-eye coordination, reflexes, and overallfitness. It is a fun and engaging way to stay active and maintain a healthy lifestyle.In conclusion, ping pong offers valuable lessons that can be applied to various aspects of life. From teaching us focus and concentration to promoting quick thinking and decision-making, ping pong inspires us to be resilient, work as a team, and lead a healthy lifestyle. So let's pick up a paddle and enjoy the benefits that ping pong has to offer!。
2022年普通高等学校招生全国统一考试英语本试卷共10页，满分120分。
考试用时120分钟。
注意事项：1. 答卷前，考生务必用黑色字迹钢笔或签字笔将自己的姓名、考生号、考场号和座位号填写在答题卡上。
用2B铅笔将试卷类型(A)填涂在答题卡相应位置上。
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1. What will the speakers do next?A. Check the map.B. Leave the restaurant.C. Park the car.2. Where are the speakers?A. At a bus stop.B. At home.C. At the airport.3. What did the speakers do last week?A. They had a celebration dinner.B. They went to see a newborn baby.C. They sent a mail to their neighbors.4. Why does the man make the phone call?A. To cancel a weekend trip.B. To make an appointment.C. To get some information.5. What does the man probably want to do?A. Do some exercise.B. Get an extra key.C. Order room service.第二节(共15小题；每小题1.5分，满分22.5分)听下面5段对话或独白。
乒乓球的起点作文英语Title: The Origin and Evolution of Table Tennis。
Table tennis, also known as ping pong, is a sport loved and played by millions around the globe. Its origins date back to the late 19th century, where it emerged as a parlor game among the elite in England. Let's delve into the fascinating journey of how table tennis came into existence and evolved into the thrilling sport it is today.The roots of table tennis can be traced back to the Victorian era, where upper-class English families indulged in various indoor games to entertain themselves. Among these games was "whiff-whaff," a precursor to modern table tennis. Players would use makeshift equipment like cigar box lids for paddles and rounded corks from wine bottles as balls, hitting them back and forth across a table.The game gained popularity among the social elite, spreading to country houses and even royal palaces. It wasduring one such gathering at the estate of the Duke of Devonshire in 1890 that table tennis took a significantstep forward. British army officer Major Walter Clopton Wingfield, who was also credited with inventing lawn tennis, introduced celluloid balls and cork paddles, which improved the game's speed and bounce.However, it wasn't until the early 20th century that table tennis began to resemble the sport we know today. In 1901, James W. Gibb, an English enthusiast, discovered the game while visiting the United States. He brought it backto England and introduced it to his friends. The gamequickly caught on, leading to the formation of the Table Tennis Association in 1921.The 1920s saw the standardization of equipment and rules, with the International Table Tennis Federation (ITTF) being founded in 1926. The first official World Championships were held in London in 1926, furthersolidifying table tennis as a legitimate sport on the international stage.Table tennis continued to evolve over the decades, with innovations in equipment, playing styles, and techniques. One significant development was the switch from hardbat to sponge rubber paddles in the 1950s, which revolutionized the game, allowing for greater spin and speed.The sport's popularity surged during the mid-20th century, particularly in Asia. Players from countries like China, Japan, and Korea dominated the international scene, showcasing incredible skill and technique. The rivalry between these nations fueled the sport's growth and led to some of the most memorable matches in table tennis history.In the 1980s, table tennis made its debut as an Olympic sport at the Games in Seoul, South Korea, further cementing its status as a global phenomenon. Since then, it has become a permanent fixture at the Olympics, captivating audiences with its fast-paced action and thrilling rallies.Today, table tennis continues to thrive, with millions of enthusiasts participating in clubs, leagues, and tournaments worldwide. The sport has also embracedtechnology, with advances in equipment and training methods pushing the boundaries of what is possible on the table.In conclusion, the journey of table tennis from its humble beginnings as a parlor game to its current status as a dynamic Olympic sport is a testament to its enduring appeal and evolution. As we look to the future, one thing is certain: table tennis will continue to inspire and captivate players and fans alike for generations to come.。
This article appeared in a journal published by Elsevier.The attached copy is furnished to the author for internal non-commercial research and education use,including for instruction at the authors institutionand sharing with colleagues.Other uses,including reproduction and distribution,or selling or licensing copies,or posting to personal,institutional or third partywebsites are prohibited.In most cases authors are permitted to post their version of thearticle(e.g.in Word or Tex form)to their personal website orinstitutional repository.Authors requiring further informationregarding Elsevier’s archiving and manuscript policies areencouraged to visit:/copyrightDiversity and evolution of Pong -like elements in Bambusoideae subfamily Hao Zhong 2,Mingbing Zhou 1,Chuanmei Xu,Ding-Qin Tang *The Nurturing Station for the State Key Laboratory of Subtropical Silviculture,Zhejiang A &F University,LinAn 311300,Zhejiang Province,PR China a r t i c l e i n f oArticle history:Received 6April 2010Accepted 26June 2010Keywords:BambusoideaeDiversityEvolutionPong -like elements a b s t r a c t The PIF /IS5is a recently discovered superfamily of DNA transposons which include Pong -like elements and PIF -like elements and has been successively detected in the genomes of many flowering plants,fungi and diverse animals.Here we present the first comprehen-sive characterization and analysis of Pong -like elements in Bambusoideae subfamily.Eighty-two Pong -like elements were cloned and sequenced from 44representative species of Bambusoideae.Phylogenetic analysis of 82distinct Pong -like elements sequences showed that Pong -like elements were widespread,diverse and abundant in Bambusoideae.A molecular phylogeny of Bambusoideae was established by using the internal transcribedspacer sequence of nuclear ribosomal DNA (ITS)information.The comparison between ITSand Pong -like elements based trees reveals obviously incongruent.The results suggest that1)there are multiple Pong -like element families in Bambusoideae;2)a single Pong -likeelement family could be present in multiple bamboo species;3)Pong -like elements fromthe same family from different bamboo species could be more similar than elements fromdifferent families in the same bamboo species or closely related species.Ó2010Elsevier Ltd.All rights reserved.1.IntroductionThe bamboo subfamily (Bambusoideae)is a division of the grasses (Poaceae)and is further divided into nine subtribes comprising 77genera and about 1030species worldwide (Soderstrom and Ellis,1987;Drans field and Widjaja,1995).Bamboo can be classi fied as woody,herbaceous or liana according to growth characteristics,and grows predominantly in tropical and subtropical regions although a few species grow in temperate and frigid zones (Chen et al.,2003).In China,there are 48genera and nearly 500species,among which Phyllostachys pubescens accounts for over two-thirds of commercially planted bamboo because of its high economic value.Many different cultivars or forms of Ph.pubescens with diverse phenotypes have been produced during its long cultivation history (Fu,2001),and fewer AFLP and SSR diversity was observed among these cultivars and forms (Lin et al.,2009;Tang et al.,2010).Additionally,long term in vitro culture induces stable changes in leaf color in Bambusa oldhamii in our lab.The mechanisms of variations are still not clear.One of the possible mechanisms to explain variation may be the activation of transposable elements (Bennetzen,2000).Transposable elements are sequences of DNA that can move around to different positions within the genome of a single cell,which are divided into class I and class II according to mechanism of transposition.Class I elements (retrotransposons)transpose by means of an RNA intermediate in a reaction involving several enzymes of reverse transcriptase and integrase.In contrast,class II elements (DNA transposons)move directly via DNA and the transposition reaction is catalyzed by a transposase encoded by autonomous DNA transposons (Bennetzen,2000;Feschotte et al.,2002).*Corresponding author.Tel.:þ8657163748811;fax:þ8657163732738.E-mail address:tang@ (D.-Q.Tang).1These authors contributed equally to this work.2Who now works in China National Bamboo ResearcherCenter.Contents lists available at ScienceDirectBiochemical Systematics and Ecologyjournal homepage:/locate/biochemsyseco0305-1978/$–see front matter Ó2010Elsevier Ltd.All rights reserved.doi:10.1016/j.bse.2010.06.010Biochemical Systematics and Ecology 38(2010)750–758H.Zhong et al./Biochemical Systematics and Ecology38(2010)750–758751Miniature inverted-repeat transposable elements(MITEs)are reminiscences of class II nonautonomous transposable elements with high copy number and intra-family homogeneity in size and sequence(Wessler et al.,1995).The mPing was thefirst active MITE identified in rice(Jiang et al.,2003;Kikuchi et al.,2003),and Pong transposon has been identified as the most likely source of mPing transposase(Jiang et al.,2003).Many transposases from nematodes,fungus,animals and plants with homologous motifs of Pong in rice were named Pong-like transposable elements(Zhang et al.,2004).Pong-like elements contain ORF1and ORF2,of which ORF2most likely encodes the transposase because it contains an apparent DDE motif,a signature consisting of three acidic residues found in the catalytic domains of some eukaryotic and prokaryotic transposases(Rezsohazy et al.,1993;Mahillon and Chandler,1998;Jiang et al.,2003).The domain of amino acids surrounding the acidic triad is relatively well-conserved and thus has served to establish the evolutionary relationships of Pong-like transposon elements in plants(Zhang et al.,2004).In this study we performedfirst comprehensive analysis Pong-like superfamily of transposases in Bambusoideae by PCR with newly designed degenerate primers.Phylogenetic analyses of82Pong-like transposase fragments from44representative species of bamboo indicated that multiple divergent lineages of Pong-like transposases coexisted within a single plant parison with the phylogenetic data of ITS information shows that there are multiple Pong-like element families in Bambusoideae,and a single family could be present in multiple bamboo species,and Pong-like elements from the same family from different species could be more similar than elements from different families in the same bamboo species or closely related species.2.Materials and methods2.1.Bamboo materials and DNA extractionAccording to taxonomy of bamboo(Soderstrom and Ellis,1987;Geng and Wang,1996;Li,1997;Das et al.,2008),we selected44representative species from38genera of6subtribes mainly distributing in China.In the intra-species level,we also selected9cultivars or forms derived from Ph.pubescens,which showing morphological differences in stem shape and color,and leaf color(Lin et al.,2009).Bamboo species and its cultivars or forms examined along with their taxonomic classification and voucher are listed in Table1.Oryza sativa ssp.japonica cv.Nipponbare was collected for cloning of ITS fragment used as outgroup of phylogenic tree based on bamboo ITS sequences.Young leaves were sampled from each species (cultivars or forms)and desiccated for DNA extraction.Genomic DNA was extracted using the method of hexadecyltrimethyl-ammonium bromide(CTAB)(Doyle and Doyle,1987)with a few modifications.2.2.PCR amplification and sequencing of Pong-like transposasesDegenerate primers(Pong-5:GGCWCCATYGAYTGTATGCAC,Pong-3:YTCGTCYTCVACYATCATRTTGTG)used to detect the Pong-like elements were derived from the regions encoding amino acid residues motifs GTIDCMH and NMIVEDE conserved in Pong-like transposases of mostflowering plants.PCR amplifications were performed with50–100ng of genomic DNA,0.2mmol/L primer pair(synthesized by Shanghai Sangon Biological Engineering Technology&Services Co.,Ltd),2units ExTaq Polymerase,1ÂPCR buffer(10mmol/L Tris–HCl,pH8.3at25 C;50mmol/L KCl),1.5mmol/L MgCl2,and0.2mmol/L of dNTP each(TaKaRa Japan)in afinal reaction volume of20m L.Cycling temperature parameters were:1cycle at94 C for5min,35cycles at94 C for60s,57 C for40s,72 C for1min,and1cycle at72 C for5min.ITS have been proved to be better marker for systematic analysis for bamboo species(Guo and Li,2004;Yang et al.,2008).Bamboo and O.sativa ITS sequences were amplified using primers ITS5and ITS4were used to amplify the whole ITS region as described by White et al.(1990).The thermal cycling comprised30cycles at94 C for 1.5min,at55 C for2min primer annealing,at72 C for1min,followed by afinal extension step at72 C for7min.Both Pong-like element and ITS PCR amplification products were resolved by1%agarose gels electrophoresis,purified using the EZ-10Spin Column DNA Gel Extraction Kit(Biobasic Inc.)and ligated into the pUC18Vectors(TaKaRa,Japan)for cycle sequencing using BigDye terminator V1.3system(PE Applied Biosystems)on an ABI PRISM3100-Avant according to the manufacturer’s instructions.For Pong-like element detection,one positive clone of Pong-like element for each species was selected for sequencing.For intra-species of Ph.pubescens in order to identify as many Pong-like transposases as possible many independent positive clones were selected from each of its cultivars or forms for sequencing until at least three repeat clones were detected for every species.For ITS regions identified,one positive clone from44representative species and O.sativa was selected for sequencing.The resulting82Pong-like transposase sequences and45ITS sequences were deposited in the NCBI GenBank database(accession numbers GU350795–GU350876and GQ464804–GQ464847,GU205182).Each element was denominated using thefirst letter of the genus name and thefirst letter of the species name followed by the clone number,for example:Bm-1for Bambusa multiplex Pong-like element clone1.Pong-like transposases which were obtained by database searches were named according to the species initials followed by NCBI accession no.by Zhang et al.(2004).2.3.Database searching and phylogenetic analysisDatabase searches for the known Pong-like elements were performed with BLAST servers available from the NCBI nr,gss, est and wgs databases()as well as the TIGR rice genomic database(/euk-blast/index).Nucleotide sequences of Pong-like elements from database and PCR amplification were conceptually translated into amino acid sequences.The translated amino acid sequences of Pong-like elements and ITS nucleotide sequences were aligned using CLUSTALW(Thompson et al.,1994)with default parameters,respectively.The best-fit model of nucleic substitution of Pong -like element and ITS sequences was tested by software Modeltest 3.7(Posada and Crandall,1998)with Akaike information criterion (Sullivan and Joyce,2005).GTR model (GTR þI þG)was the optimum for Pong -like elements and TIMef þI þG was the optimum for ITS sequences.The phylogenetic relationships among the bamboo Pong -like elements were investigated from either the nucleic consensus sequences or their in silico translation into protein sequences,while the phylogenetic relationships among Bambusoideae were investigated from the ITS nucleic sequences.AllTable 1H.Zhong et al./Biochemical Systematics and Ecology 38(2010)750–758752phylogenetic trees were generated using neighbor-joining(NJ),maximum parsimony(MP),maximum likelihood(ML)with PAUP software v4.0b10(Swofford,2002)and Bayesian inference(BI)with MrBayes v3.1.2(Ronquist and Huelsenbeck,2003),and reswapped with NEAREST NEIGHBOR INTERCHANGE by using Molphy v2.3b3(Adachi and Hasegawa,1996).Rearranged topol-ogies were very similar to those initially generated by four methods,at least for the groupings discussed in this study.3.Results3.1.Identification and polymorphism of transposases of Pong-like elements in the Bambusoideae subfamilyA pair of degenerate primers was designed to amplify a fragment of the transposase gene containing“DDE”domain of Pong-like transposase(Zhang et al.,2004).PCR with the degenerate primers yielded one uniform size fragment of approx-imately520-bp for each bamboo species(Fig.1).Taken together,82amplification fragments from44representative species and9Ph.pubescens cultivars or forms were obtained and sequenced.At the amino acid level,the bamboo sequences showed between67.2%and79.1%identity with an identified typical Pong-like element from O.sativa(OsBK000586,accession number BK000586)(data not shown).At least one representative species were selected from six subtribes(Melocanninae,Bambusinae,Shibataeeae,Chusqueeae,Arundinarieae and Guaduinae)for detecting the conserved functional domains regions.Several blocks of highly conserved residues were consistent with those of Pong-like transposases which most likely comprise the catalytic domain.The conserved amino acid residues of DDE motif were identified in all fragments.First D is present at the position4,second D present at the position94and the E present at the position171of the consensus amino acid sequence(Fig.2).The data confirmed that the all PCR products contained the DDE region of the Pong-like transposase genes.Almost all82sequences of Pong-like transposases we cloned in bamboo species were unique.Pairwise comparison showed 57.8–99.6%identity at the nucleotide sequences level and54.9–100%identity at the amino acid level(supplementary Tables1, 2).Comparison within each subtribe revealed90.6%identity among the Guaduinae,71.7–86.7%among the Melocanninae,63.3–97.1%among the Bambusinae,62.7–100%among the Shibataeeae,and61.8–100%among the Arundinarieae at amino acid level (supplementary Table2).The results indicate Pong-like transposases are highly polymorphic in bamboo species tested.3.2.Phylogenetic position of bamboo Pong-like elements inflowering plantsUp to date,at least three subfamilies of Pong-like elements have been reported inflowering plants,i.e.,clade O,clade P and clade Q,of which Clade O and Clade P can be further classed into subclade O1,O2and subclade P1,P2,respectively(Zhang et al.,2004).In order to place the above characterized bamboo Pong-like elements in this phylogenetic tree,several elements representing each of the three subfamilies previously reported(Zhang et al.,2004)were aligned with bamboo Pong-like elements.Three Pong-like transposase clusters similar to the clades mentioned above are shown and are defined as the largest well-supported monophyletic group of sequences obtained from phylogenetic trees generated by four distinct methods(NJ,MP,ML and BI,all bootstrap values>63%,Fig.3).Most of bamboo Pong-like elements clustered in two branches of tree.First,significant portion of bamboo Pong-like elements grouped into clade Q(bootstrap value of78%).Second,the three bamboo Pong-like elements grouped into subclade O2(bootstrap value of100%).It was noted that there were three bamboo Pong-like elements which could not grouped into any clades defined by Zhang et al.(2004)and clustered as new clade BaS(bootstrap value of82%).3.3.Evolution of bamboo Pong-like elementsTo analyze of phylogenetic relationships among Bambusoideae Pong-like elements,phylogenetic tree was generated from amino acid sequences of the44representative species that were selected to represent the different lineages within each subtribe with one PIF-like element from a fungus(Filobasisiella neoformans)as the outgroup(Fig.4A).Meanwhile the analysis of ITS sequences allowed the construction of a parallel tree showing the phylogenetic relationship among the same44bamboospecies with the ITS sequence from O.sativa as outgroup(Fig.4B).The ITS tree supported the existence of six subtribes,i.e.Fig.1.Detection of Pong-like transposase genes in bamboo subfamily by using PCR with degenerate primers.Representative examples are shown from10species. M:100-bp ladder.1.Sasa fortunei,2.Bashania fargesii,3.Acidosasa gigantean,4.Himalayacalamus intermedia,5.Chimonobambusa marmoreal,6.Semiarundinaria fastuosai,7.Dendrocalamus minor,8.Indosasa shibataeoides,9.Hibanobambusa tranguillans,10.Schizostachyum funghomii.H.Zhong et al./Biochemical Systematics and Ecology38(2010)750–758753Melocanninae,Bambusinae,Shibataeeae,Chusqueeae,Arundinarieae,Guaduinae.In contrast,44Pong -like elements from Bambusoideae grouped into 4clusters (QBaI,QBaII BaS and O2)which indicated that there are four Pong -like element families in Bambusoideae and a single family could be present in multiple species.It is also noted that Pong -like elements from the same family from different species could be more similar than elements from different families in the same bamboo subtribes or closely related species.For example,Ht-1Pong -like element (Hibanobambusa tranguillans )was 100%identity with Ss-1Pong -like element (Sasa sinica )at the amino-acid level,while they are from subtribes of Shibataeeae and Arundinarieae,respectively.InFig.2.Structure and conserved coding regions of the ampli fication fragments of Pong -like elements.Multiple alignments of conceptually translated ampli fication fragments from bamboo Pong -like elements are shown.Horizontal arrows indicate the annealing position of the dPCR primers,and DD37E motifs in transposases are indicated by asterisks.A consensus sequence of OsBK000586,the Pong -like elements in rice is shown above alignments for comparison.Sequences were named according to the species initials followed by their clone number (Table 1for abbreviations).H.Zhong et al./Biochemical Systematics and Ecology 38(2010)750–758754contrast,Pong -like elements from the same bamboo subtribes or closely related species could be more divergent than that from different subtribes species or distant related species,e.g.two diverse Pong -like transposases subclades were present in Melo-canninae group,Pp-1,Ms-1and Mb-1from subclade QBa I shared 72.4%–75.3%identity with Sf-1and Cp-1from the clade QBaII.The phenomenon was farther supported by the analysis of phylogenetic relationships among intra-species Pong -like trans-posases.Another phylogenetic tree was constructed from 39amino acid sequences from nine different cultivars or forms of Ph.pubescens (Fig.4C).All Pong -like transposases from cultivars or forms of Ph.pubescens belong to clade Q.They could further be clustered into three subclades names as QPhI,QPhII and QPhIII.Pong -like elements from the same cultivars (such as PhK-1and PhK-2from Ph.pubescens cv.Heterocycl a )demonstrated a 43.1%lower level of identity than that from different cultivars (such as PhO-1from Ph pubescens cv.Obliquinoda).This revealed that Pong -like elements have evolved relatively independent of taxonomy of bamboo and even one individual may display more than one subclade of Pong -like elements in its genome.4.Discussion4.1.Pong -like elements were widespread and abundant in Bambusoideae subfamilyThe PIF /IS5is a recently discovered superfamily of DNA transposons which include Pong -like elements and PIF -like elements and has been successively detected in the genomes of flowering plants,fungi and animals (Le et al.,2001;Zhang et al.,2001,2004;Kapitonov and Jurka,2004).Here we present the first comprehensive characterization and analysis of Pong -like elements in Bambusoideae subfamily.Of all 9subtribes in Bambusoideae subfamily,6subtribes including 44speciesFig.3.Phylogenetic position of bamboo Pong -like elements in the plant Pong -like elements family.The phylogenetic tree was generated by multiple alignments of 95catalytic DDE motifs of Pong -like transposase fragments including 82from 44representative species of Bambusoideae subfamily isolated by PCR and 13obtained by database searches which were marked by circles.Main bootstrap values (1000replicates)are shown.Groupings de fining lineages and sublineages of plant Pong -like transposases are emphasized by capital letters and different colors.Sequences were named according to the species initials followed by the number of the clone (see Table 1for abbreviations),Os ¼Oryza sativa (rice),Lj ¼Lotus japonicas ,At ¼Arabidopsis thaliana ,Bo ¼Brassica oleracea ,Sb ¼Sorghum bicolor .H.Zhong et al./Biochemical Systematics and Ecology 38(2010)750–758755of 38genera mainly distributed in China were selected for testing materials.These tested bamboo species covered type of woody (most species)and liana (Melocalamus arrectus ,etc.),distributed in as south to equatorial America (Guadua angus-tifolia )and north to temperate regions (Phyllostachys species in Beijing)(Clayton et al.,2006).All the species studied displayed Pong -like elements in their genome by degenerate primers PCR ampli fication.Almost all the sequences of cloned products were unique and diverse with 57.8–99.6%identity at the nucleotide sequences level,of which three sequenceswereFig.4.Phylogenetic analysis of Pong -like transposase fragments and ITS sequences within the Bambusoideae subfamily.Sequences were named according to the species initials followed by the number of the clone (see Table 1for abbreviations).Main bootstrap values (1000replicates)are shown.Groupings de fining lineages and sublineages of bamboo Pong -like transposase are emphasized by capital letters and different colors,:Shibataeeae;:Arundinarieae;:Melocanninae;:Bambusinae;-:Guaduinae;:Chusqueeae.A.Phylogenetic relationships among bamboo Pong -like transposase fragments.The phylogenetic tree was generated by multiple alignments of 44Pong -like transposase fragments obtained by PCR from representative bamboo species.B.Phylogenetic relationships of ITS sequences from the same representative bamboo species,obtained as above.C.Phylogenetic relationships among 39Pong -like transposase fragments isolated from 10Ph.pubescens cultivars or forms,obtained as above.H.Zhong et al./Biochemical Systematics and Ecology 38(2010)750–758756H.Zhong et al./Biochemical Systematics and Ecology38(2010)750–758757 species-specific of bamboo(Clade BaS).Intra-species level,39Pong-like elements from Ph.pubescens and its cultivars or forms were identified.Sequencing of5PCR products from Ph.pubescens showed as different Pong-like elements.All the results show that Pong-like elements are indeed abundant and heterogeneous in the Bambusoideae subfamily.Genome-wide analysis identified total80Pong-like elements in O.sativa(Zhang et al.,2004).The DNA contents of bamboo were2.45–5.3pg DNA/2C,and the temperate bamboo(Phyllostachys species)falling within the range4.17–5.3pg(Gielis et al., 1997).The genome size of Ph.pubescen s was estimated to be about2034Mb,approximately5.4times that of the diploid cultivated rice(Gui et al.,2007).Given that amplification of transposable elements is largely responsible for the huge differences in plant genome size(Bennetzen,2002;Feschotte et al.,2002),it is reasonable to assume that even larger families of Pong-like transposable elements will be found once bamboo genomes are sequenced.4.2.Evolution of Pong-like transposable elements in Bambusoideae subfamilyThe significant portion of Pong-like elements from Bambusoideae subfamily in this study could be clustered into clade Q and several into subclade O2.Clade Q has been proved to be ancient origin in plant Pong-like elements family(Zhang et al., 2004).The available fossil evidence and the surviving basal lineages suggested the Bambusoideae were evolved in Gond-wanaland during the upper Cretaceous of more than65Myr ago(Guo et al.,2002).The results suggest that most Pong-like elements from Bambusoideae subfamily are likely transposable elements of ancient origin.We constructed a comparative ITS-based phylogeny of Bambusoideae subfamily which agrees with the previous analyses based on morphologic and molecular characters(Soderstrom and Ellis,1987;Li,1997;Das et al.,2008;Yang et al.,2008).The phylogenetic tree constructed with the Pong-like element sequences was obviously incongruent with the ITS-based phylogeny. The incongruence was particularly reflected by the presence of near identical Pong-like elements from distantly-related species and the presence of very diverse Pong-like elements within the same cultivars of Ph.pubescens.There are at least four alternative hypotheses to explain the result.First,Pong-like elements analyzed from44representative bamboo species in this research are most likely paralogous not orthologous because of high heterogeneity(supplementary Tables1,2).Second,bamboo Pong-like elements originated from different ancestors(Fig.4A,C).In every clade,divergent evolution of different ancestors might be different.Ancestral duplication and/or polymorphism may create paralogous copies of transposable elements that evolve distinctly in different genomes(Davis and Wurdack,2004;Mower et al.,2004).Third,usually,transposable elements suffer more tough natural selection than other sequences due to their potential impact of transposition on the host genome.There are at least three deleterious effects of transposable elements in the host genome including mutations resulting from insertions into genes or regulatory sequences(Finnegan,1992),chromosomal rearrangements caused by ectopic recombination between elements in non-homologous insertion sites(Montgomery et al.,1987)and direct costs due to its transposition activity (Brookfield,1991).So the sequences of transposable elements provide a more robust target for natural selection than other sequences(Pritham,2009).When transposon activity is suppressed,such elements could be eliminated from the population by stochastic loss or vertical extinction,a process that may occur in one species but perhaps not in a closely related one(Hartl et al., 1997).Fourth,horizontal transfer might be another potential explanation about the incongruence.The scenario of horizontal transfer remains a remote speculation,until a common transmission vector is identified(Capy et al.,1998;Won and Renner, 2003;Bergthorsson et al.,2004;Richardson and Palmer,2007).Although hundreds of Pong-like element sequences were identified by database search there is so far no clear indication for any horizontal movement of Pong-like elements among plants(Zhang et al.,2004).In this study,82Pong-like element sequences were isolated from bamboo and phylogenetic analysis of these sequences could not prove beyond doubt the occurrence of horizontal rge-scale sequencing of bamboo species would allow to the evolution of Pong-like elements to be studied in more details.AcknowledgmentsWe are grateful to Ma Naixun of Research Institute of Subtropical Forestry and Xingchun Lin of Key Lab for Modern Silvicultural Technology of Zhejiang Province for their advices on sketching the sampling strategies.This work was supported by a special grant from the National Natural Science Foundation of China(grant nos.30371181and30771753)and Talents Program of Natural Science Foundation of Zhejiang Province(grant no.R303420).Appendix.Supplementary informationSupplementary data associated with this article can be found in the online version at doi:10.1016/j.bse.2010.06.010. 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