理工英语4第一单元
英语综合教程4第一单元作文范文
英语综合教程4第一单元作文范文English:In Unit 1 of English Integrated Course 4, the theme focuses on the concept of success and how different people interpret it. Success can be seen as achieving goals, fulfilling dreams, or making a difference in the world. It varies from person to person and is not always defined by wealth, fame, or power. The unit encourages students to reflect on what success means to them personally and consider the importance of personal growth, happiness, and relationships in the journey towards success. Through thought-provoking readings, discussions, and activities, students are challenged to think beyond conventional definitions of success and explore the deeper meaning and fulfillment that comes from following their passions and values.中文翻译:在英语综合教程4的第一单元中，主题集中在成功的概念以及不同人如何解释成功。
成功可以被视为实现目标，实现梦想，或在世界上产生影响。
2020年最新电大《理工英语4》考试(题目和答案)
2020年最新电大《理工英语4》考试(题目和答案)1.交际用语：如果免费，你会做整形手术吗？A。
不会。
良好的饮食和运动是很好的替代方法。
B。
是的，我不会做。
C。
不，我会做。
改写：问及免费整形手术，回答者可以选择不会或会。
但是，良好的饮食和运动也是很好的替代方法。
2.交际用语：好的，我现在就修好你的电脑。
哦，慢慢来。
A。
我受不了。
B。
我不着急。
C。
那是个好主意。
改写：当被告知电脑将被立即修复时，回答者可以选择表现出不着急的态度。
3.交际用语：是外表好看还是聪明更重要？A。
是的，外表很重要。
B。
不，外表不重要。
C。
对我来说，聪明更重要，但这取决于情况。
改写：问及外表和聪明的重要性，回答者可以选择认为聪明更重要，但也取决于具体情况。
4.交际用语：你每天都吃粥吗？A。
粥是我最喜欢的食物。
B。
不，有时我会选择豆浆、煮蛋和馒头作为早餐。
C。
我很少吃快餐，因为它富含脂肪。
改写：问及每天是否吃粥，回答者可以选择否认，并分享自己的早餐选择。
5.交际用语：请问，机场离这里有多远？A。
你可以坐出租车。
B。
大约30英里。
C。
我要飞往悉尼。
D。
只需要600美元。
改写：询问机场距离，回答者可以提供距离信息或其他相关信息，如出租车选项或飞往其他城市的计划。
6.I am really fascinated by the use of fresh ingredients。
intricate cooking techniques。
XXX cuisine.7.When you reach the age of 75.you may apply for a free Over75 TV License.8.They are expected to make an XXX.9.The current death rate has been ced by 10% compared to that of the year 1980.10.XXX。
大英四unit1英语作文
大英四unit1英语作文英文回答：In the realm of education, the profound impact of technology has sparked a heated debate regarding whether it enhances or hinders the learning experience. While someextol the transformative potential of technology, others raise concerns about its potential drawbacks. In this essay, I will explore both sides of this multifaceted argument, delving into the benefits and challenges of integrating technology into the classroom.On the one hand, technology offers an array of advantages that can revolutionize the way students learn. Interactive simulations, immersive virtual reality experiences, and sophisticated data analytics empower students to engage with complex concepts in a more dynamic and engaging manner. Personalized learning platforms tailor educational content to the individual needs of each student, allowing them to progress at their own pace and focus onareas where they need additional support. Furthermore, technology fosters collaboration and peer-to-peer interaction, breaking down geographical barriers and enabling students to learn from diverse perspectives.On the other hand, it is crucial to acknowledge the challenges associated with the integration of technology in the classroom. Excessive screen time can lead to eye strain, headaches, and other health concerns. Additionally, the constant bombardment of digital distractions can hinder students' ability to focus and retain information. Moreover, the digital divide presents a significant obstacle, as not all students have equal access to technology and the resources it offers. Finally, the rapid pace oftechnological advancement can make it challenging for educators to keep up and ensure that technology is used effectively and appropriately.To strike a harmonious balance, it is essential to approach the use of technology in the classroom with a thoughtful and nuanced perspective. Rather than embracing technology as a panacea, educators should carefullyconsider its potential benefits and risks and integrate it into the curriculum in a way that complements traditional teaching methods. By providing adequate training and support for both students and educators, it is possible to harness the transformative power of technology while mitigating its potential pitfalls.Ultimately, the question of whether technology enhances or hinders the learning experience is a complex one with no easy answer. By recognizing the advantages and disadvantages of technology and adopting a balanced approach, educators can leverage this powerful tool to empower students and foster a dynamic and engaging learning environment.中文回答：科技对学习的影响。
理工英语4作业1作文
The Evolution of Technology and Its Impacton Our LivesIn the fast-paced world of today, technology is constantly evolving, shaping the way we live, work, and interact with each other. From the industrial revolution to the digital age, technological advancements have brought about profound changes in society, transforming the way we view the world and our role within it.The industrial revolution marked a significant milestone in the history of technology. With the invention of steam power, mechanized looms, and other innovative machinery, production rates skyrocketed, leading to unprecedented economic growth. This period saw the emergence of factories and large-scale urbanization, as people migrated to cities to take advantage of the new job opportunities. However, this rapid industrialization also led to environmental degradation and social upheaval, highlighting the need for a balanced approach to technological development.The advent of the digital age has furtherrevolutionized our lives. The widespread adoption ofcomputers, smartphones, and the internet has made information more accessible and interconnected than ever before. We can now stay connected with friends and family across the globe, access vast libraries of knowledge, and accomplish tasks with unprecedented efficiency. Additionally, digital technology has given rise to new industries and job opportunities, such as e-commerce, software development, and data analytics.However, the rise of digital technology has also presented new challenges. Cybersecurity threats are becoming increasingly sophisticated, and protecting personal information and sensitive data is crucial. Furthermore, the widespread use of digital devices has led to concerns about digital addiction and its potential impact on mental health.Despite these challenges, the future of technology looks bright. Advancements in areas such as artificial intelligence, robotics, and biotechnology are expected to bring even more profound changes to our lives. We can imagine a future where self-driving cars navigate the streets safely, where robots assist us in our daily tasks,and where personalized medicine tailors treatments to our individual needs.In conclusion, the evolution of technology has had a profound impact on our lives, shaping the way we live, work, and interact with each other. While it has brought about remarkable advancements and opportunities, it has also presented new challenges that we need to address. As we move forward into the future, it is crucial that wecontinue to innovate responsibly, ensuring thattechnological advancements serve the needs of society and contribute to our overall well-being.**技术演变及其对我们生活的影响**在当今快节奏的社会中，技术不断演变，塑造着我们的生活方式、工作方式和彼此之间的交往方式。
《理工英语4》第一套
交际用语（共5题，共10分）1. —Oh. Dear! I’ve lost my new watch.—_________________A I’m sad.B That’s all right.C What a pity!2. — I'm leaving for Shanghai tomorrow.—_________________A Bring me a present.B Have a pleasant trip!C Let's go out for a drink.3. —Do you eat porridge every day?—_________________A Porridge is my favorite.B No, sometimes I’d have a cup of soybean milk, a boiled egg and a steam ed bun for my breakfast.C I seldom eat fast food because it’s rich in fat.4. —Do you mind my using my mobile phone here?— ________________A Yes, use it please.B No, you can’t use it.C No, of course not.5. —Let’s go to this movie and see what exciting experience it will bring to us.—_________________A Can’t wait to watch it.B You are such a great fan.C I am more interested in the film director.词汇与结构（共15题，共30分）1. Touch- ____ 3D maps help the blind too much.A responsiveB speakingC listening2. Animal farming______about half of all human-caused greenhouse gases.A count forB accounts forC count on3. Modern Meadow is a startup that engineers tissues to create lab-grown ______ meat.A edibleB editableC edify4. They should never try to pursue profit______health and life of people.A in terms ofB at sight ofC at the expense of5. I am really______by fresh ingredients, intricate cooking and diverse traditions of Chinese food.A fascinatedB fabricateC fancy6. They are trying to make a new product——the world’s smallest __________ robot.A hammerB humaneC humanoid7. He ______ his baggage among hundreds of others.A identifiedB awareC conscious of8. _______no modern telecommunications, we would have to wait for weeks to get news from around the world.A Were thereB If there areC If there have been9. Doctor，please let me know ____ you can reconstruct my face.A whatB whetherC which10. When we were students we_______often stay up all night.A willB wouldC should11. It is hard for any woman to resist ____ herself more beauty.A makeB madeC making12. Some illegal traders care about nothing but_______.A to make moneyB making moneyC made money13. The plastic surgeon may provide several plans for your facial ________.A reconstructB reconstructionC reconstructed14. She is ______ tall as you.A notB soC as15. _______people are no longer worried about whether their food is safe or not_______they enjoy a better life.A Only if……canB If only……canC What if……can阅读理解（共2题，共40分）1. Here's a crazy idea: Combine bioprinting and tissue engineering to "print" animal products and tackle some of the planet's biggest problems. Animal farming, after all, accounts for about half of all human-caused greenhouse gases, taking place on one-third of the available, non-frozen land on Earth. All to feed people's appetites for 300 million tons of meat a year.Modern Meadow is a Missouri-based startup that engineers tissues to create lab-grown edible meat, in a process that eliminates many of the negative environment effects associated with traditional livestock practices.The company claims that by carefully layering mixtures of cells of different types in a specific structure, in-vit ro meat production becomes feasible. It’s set a short-term goal of printing a sliver of meat around two centimeters by one centimeter, and less than half a millimeter thick, which is edible.The company explains in a submission to the United States Department of Agriculture: “The technology has several advantages in comparison to earlier attempts to engineer meat in vitro. The bio-ink particles can be reproducibly prepared with mixtures of cells of different type. Printing ensures consistent shape, while post-printing structure formation and maturation in the bioreactor facilitates conditioning.”However, it admits that the road ahead is strewn with difficulties. “The consumer acceptance of such products may not be without challenges. We expect it will first appeal to culinary early-adopter consumers and the segment of the vegetarian community that rejects meat for ethical reasons. With reduction in price, it can reach the masses with religious restrictions on meat consumption (people restricted to Hindu, Kosher, Halal diets) and finally populations with limited access to safe meat production.”Whatever the final outcome, lab-grown edible meat is no longer in the realm of science fiction. It is coming.(1). Animal farming is responsible for the occurrence of greenhouse gases.A TB F(2). Modern Meadow is a newly-started business which aims to make profits by producing lab-grown edible meat.A TB F(3). The method Modern Meadow adopted to produce in-virto meat is by layering mixtures of cells of different types in a specific structure.A TB F(4). There is no meat engineered outside living bodies before.A TB F(5). This lab-grown meat has already widely received by the masses.A TB F1. Imagine you sitting on your front garden admiring the shining sun when your neighbor comes with that annoying car with the noisy sound and the exhaust pipe blowing out the horrible black smoke. What are you going to do about it?In our modern days, too many people depend on their cars to get to work or to drop off their children to school. However, is it safe to have an increasing number of cars on our roads?Research shows that cars create serious pollution. Exhaust from all combustion engines produce harmful effects on the health of both car users and all innocent walkers. Cities have become islands of toxic chemicals from the unrestrained use of vehicles burning fossil fuels. The harmful health effects of car exhaust are pervasive and difficult to measure. For example, people with asthma would suffer with attacks due to the pollution. The world wild life also suffers from the cars’ toxic emissions. No matter how much manufacturers try to make cars environmentally friendly, it will damage our earth in one way or another.Additionally, cars are too dangerous for our community. Careless drivers putthemselves and others in danger. Cars are critical to walkers especially to children if the driver is not looking on the road or somehow distracted. Have you known someone whose toes or feet have been run over by cars while crossing the street? Lastly, cars create social problems, which could lead to poor health. A few drivers suffer “Road Rage” and put themselves, loved ones and others in a threatening situation. Some cars create disturbing noises, which disturbs people living near highways, freeways, etc. not to get enough sleep. People depend on their cars so much that they forgot to exercise their bodies and end up being obese or having a heart problem.As a result of the excessive number of cars on our roads, everyone’s life is in danger. In order to create an environmentally friendly and safe world, it is necessary for each country to limit the permits in number to control regional air pollution. Second, car manufacturers should try to improve the efficiency of vehicles, such as finding solutions to emissions of combustion engines, developing new power sources such as new fuels, natural gas. Third, try to improve efficiency of traffic by setting up dedicated bus lanes and giving priority to carpools and vehicles with 3 or more passengers. Besides, traffic can be scheduled: for example, commercial traffic at night; large companies can shift working hours and decentralizing administrative operations.(1). Exhaust from cars is ______.A harmlessB pollutiveC not serious(2). In the author’s view, it is ______ to make cars be friendly to environment.A impossibleB feasibleC hopeful(3). ______ will be the major victims in the car accident.A WalkersB ChildrenC Car-drivers(4). Cars caused some social problems EXCEPT ______.A obesityB a quick temperC employment(5). Which of the following is NOT TRUE as to handling car problems?A Reducing the number of cars.B Using a car in the restricted area.C Finding alternative fuels.主观题作文（共1题，共20分）Write a company profile according to the given information.请根据所给信息写一份公司简介。
国家开放大学《理工英语4》形考任务1-8参考答案
国家开放大学《理工英语4》形考任务1-8参考答案注：题目顺序是随机的，使用查找功能（Ctrl＋F）进行搜索国开电大理工英语4形考任务单元自测1答案"题目：_______, he knows a lot about computer.: As he is a child; Child as is he; Child as he is""题目：My assistant will now______________ the machine in action.: demonstrate; demobilize; domestic""题目：__________ this multimedia product has some shortcomings, it has also some good points.: While; If; Not only""题目：—Do you mind my using my mobile phone here?—________________.: Yes, use it please.; No, of course not""题目：—How isyour business going?—_________________: Good, it's growing all the time.; Thank you.; I’m going to Beijing. ""题目：—I wonder if Icould use your tablet tonight?—________________. I’m not using it right now.: It doesn’t matter.; No, thank you.; Sure, here you are.""题目：—Oh. Dear! I’ve lost my new watch.—_________________: I’m sad.; That’s all right.; What a pity!""题目：2.—Thank you ever so much for the Apple Watchyou sent me.—________________: No thanks.; I’m glad you like it.; Please don’t say so.""题目：Considering the needsof the new generation, we propose the concept of the _______ network.: wearing; wearable"题目：Heremotelycontrols my mobile phone _______ he can set up it for me.: that; so that; in order to""题目：If you want to download this app, you need to connect your mobile phone_______ Internet first.: to; for; with""题目：So ________that millions of people queue to buy it.: popularis the smartphone; popular the smartphone is; the smartphone is popular""题目：The BBC has just successfully demonstrated a ________ radio transmission system. : digestive; dignity; digital""题目：The speed with which digital cameras can take, process and _______ an image is phenomenal.: transmit; transact"题目：They are _______ make an announcement later on today.: wish to; expected to; looking forward to ""题目：You will quickly get used to_______ this new digital camera.: use; using; be ran"" 二、阅读理解：这是客服人员帮助客服创建进入个人账户的场景，请在空格内填入字母将对话排序。
高中英语选修四第一单元作文
高中英语选修四第一单元作文Here is an essay on the topic of "The First Unit of the English Elective Course in High School" with more than 1000 words, written entirely in English without any additional punctuation marks in the body of the text.The First Unit of the English Elective Course in High SchoolHigh school is a crucial stage in a student's academic journey where they not only acquire knowledge but also develop essential skills that will shape their future. One of the integral components of this educational experience is the English elective course, which offers students the opportunity to delve deeper into the intricacies of the English language. The first unit of this course plays a pivotal role in setting the foundation for a comprehensive understanding of the subject.The first unit of the English elective course in high school typically focuses on the fundamentals of the language, providing students with a solid grasp of grammar, vocabulary, and communication skills. This foundational knowledge serves as a springboard for more advanced concepts and applications that will be explored in thesubsequent units.One of the primary objectives of the first unit is to reinforce and expand upon the grammatical structures that students have already been introduced to in their previous English language studies. This includes a thorough review of parts of speech, sentence structures, and the proper use of verb tenses. By ensuring that students have a firm grasp of these grammatical principles, the course lays the groundwork for more complex writing and speaking exercises.In addition to grammar, the first unit also emphasizes the importance of building a robust vocabulary. Students are exposed to a wide range of words, including those commonly used in academic and professional settings. This not only enhances their ability to comprehend and articulate ideas but also prepares them for the more advanced reading and writing tasks they will encounter in the subsequent units.Another crucial aspect of the first unit is the development of communication skills. Students are encouraged to engage in various activities that promote effective oral and written expression. This may include group discussions, presentations, and written assignments that challenge them to organize their thoughts, articulate their ideas, and communicate them clearly and concisely.The first unit also introduces students to the fundamentals of academic writing, which is a crucial skill for success in higher education and beyond. Students learn the basic structure of an essay, including the introduction, body paragraphs, and conclusion. They are also taught the importance of developing a clear thesis statement, supporting their arguments with relevant evidence, and maintaining a coherent and logical flow throughout their writing.Furthermore, the first unit often includes an introduction to literary analysis, where students begin to explore the nuances of literary devices, such as symbolism, metaphor, and theme. This exposure to the close reading and interpretation of literary texts lays the groundwork for more advanced literary analysis in the subsequent units.One of the unique features of the first unit is its emphasis on the integration of language skills. Rather than treating grammar, vocabulary, and communication as separate entities, the course aims to demonstrate how these various components work together to enhance overall language proficiency. This holistic approach helps students understand the interconnectedness of the different aspects of the English language and prepares them for the more complex and multifaceted tasks they will encounter in the later units.Moreover, the first unit often incorporates a cultural component,exposing students to the rich diversity of the English-speaking world. This may include the study of literature, films, or other cultural artifacts from different regions and time periods, allowing students to develop a deeper appreciation for the global reach and influence of the English language.In conclusion, the first unit of the English elective course in high school lays the foundation for a comprehensive understanding of the English language. By focusing on grammar, vocabulary, communication skills, academic writing, and literary analysis, the course equips students with the necessary tools to navigate the more advanced concepts and applications that will be explored in the subsequent units. This holistic approach to language learning not only strengthens students' linguistic abilities but also fosters a deeper appreciation for the richness and diversity of the English language.。
理工英语4 Self-test答案-unit 1
理工英语4 Self-test答案Unit 1一、选择填空：阅读下面的对话或句子，从A、B、C三个选项中选出一个能填入空白处的最佳选项。
1.—I wonder if I could use your tablet tonight?—________________. I’m not using it right now.选择一项：Ca. It doesn’t matter.b. No, thank you.c. Sure, here you are.2.—Do you mind my using my mobile phone here?— ________________.选择一项：Ba. Yes, use it please.b. No, of course not3.—Oh. Dear! I’ve lost my new watch.—_________________选择一项：Ca. I’m sad.b. That’s all right.c. What a pity!4.They are _______ make an announcement later on today.选择一项：Ba. wish tob. expected toc. looking forward to5. Here motely controls my mobile phone _______ he can set up it for me.选择一项：Ba. thatb. so thatc. in order to二、阅读理解：阅读下面的短文，根据文章内容进行判断，正确写“T”错误写“F”。
Baidu, China's leading search engine company, has unveiled its own eyewear called Baidu Eye. It is said to be a different product from Google Glass in terms of functionality.The company demonstrated a working prototype on September 3 at its annual Technology Innovation Conference in Beijing. It bears a similarity to Google Glass, but it has no screen. Instead, the device uses a camera to scan objects, and focuses on analyzing information around its user and beaming that to a smartphone. Baidu says the device is designed to support image search. The company's CEO Robin Li believes in five years' time, people will get used to searching by image and audio rather than text. Li has given an example of how one can take advantage ofBaidu Eye, "If you are in a shopping mall and come across a woman whose skirt looks really attractive, you take a photo of her skirt using Baidu Eye, and you'll get to know where to buy one for yourself."According to Kaiser Kuo, Baidu's director of international communications, Baidu Eye can also recognize voice and gesture, "You can use voice commands, or gesture commands - like expanding to zoom, or circling an object in your field of view with your finger."Baidu is yet to announce a release date or marketing plans for Baidu Eye.1.Baidu is China's leading search engine company.2.Baidulaunched a product that has more functions than Google GlassonSeptember 3.3.Baidu Eye can scan objects with its small screen.4.The company’s CEO Robin Li believes that people will get used to searching bytext.5. Baidu has already announced the release of Baidu Eye.。
- 1、下载文档前请自行甄别文档内容的完整性，平台不提供额外的编辑、内容补充、找答案等附加服务。
- 2、"仅部分预览"的文档,不可在线预览部分如存在完整性等问题,可反馈申请退款(可完整预览的文档不适用该条件!)。
- 3、如文档侵犯您的权益，请联系客服反馈,我们会尽快为您处理(人工客服工作时间：9:00-18:30)。
一、选择填空：阅读下面的对话或句子，从A、B、C三个选项中选出一个能填入空白处的最佳选项。
1、—I wonder if Icould use your tablet tonight?—________________. I’m not using it right now.c. Sure, here you are.2、—Do you mind my using my mobile phone here?— ________________.b. No, of course not3、—How isyour business going?—_________________a. Good, it's growing all the time.4、The speed with which digital cameras can take, process and _______ an image isphenomenal.c. translate5、_______, he knows a lot about computer.c. Child as he is6、—Thank you ever so much for the Apple Watchyou sent me.— ________________b. I’m glad you like it.7、—Do you mind my using my mobile phone here?— ________________.b. No, of course not8、—Oh. Dear! I’ve lost my new watch.—_________________c. What a pity!9、Considering the needsof the new generation, we propose the concept of the _______network.b. wearable10、__________ this multimedia product has some shortcomings, it has also some goodpoints.选择一项：a. While11、—I wonder if Icould use your tablet tonight?—________________. I’m not using it right now.c. Sure, here you are.12、—Oh. Dear! I’ve los t my new watch.—_________________c. What a pity!13、—How isyour business going?—_________________a. Good, it's growing all the time.14、My assistant will now______________ the machine in action.c. demonstrate15、Heremotelycontrols my mobile phone _______ he can set up it for me.c. in order to16、—Thank you ever so much for the Apple Watchyou sent me.— ________________b. I’m glad you like it.17、—I wonder if Icould use your tablet tonight?—________________. I’m not using it right now.c. Sure, here you are.18、—Oh. Dear! I’ve lost my new watch.—_________________c. What a pity!19、The BBC has just successfully demonstrated a ________ radio transmissionsystem.c. digital20、So ________that millions of people queue to buy it.选择一项：a. popularis the smartphone21、—How isyour business going?—_________________a. Good, it's growing all the time.22、They are _______ make an announcement later on today.b. expected to23、You will quickly get used to_______ this new digital camera.b. using二、阅读理解：阅读下面的短文，根据文章内容进行判断，正确写“T”错误写“F”。
（一）Baidu, China's leading search engine company, has unveiled its own eyewearcalled Baidu Eye. It is said to be a different product from Google Glass in terms of functionality.The company demonstrated a working prototype on September 3 at its annual Technology Innovation Conference in Beijing. It bears a similarity to Google Glass, but it has no screen. Instead, the device uses a camera to scan objects, and focuses on analyzing information around its user and beaming that to a smartphone.Baidu says the device is designed to support image search. The company's CEO Robin Li believes in five years' time, people will get used to searching by image and audio rather than text. Li has given an example of how one can take advantage of Baidu Eye, "If you are in a shopping mall and come across a woman whose skirt looks really attractive, you take a photo of her skirt using Baidu Eye, and you'll get to know where to buy one for yourself."According to Kaiser Kuo, Baidu's director of international communications, Baidu Eye can also recognize voice and gesture, "You can use voice commands, or gesture commands - like expanding to zoom, or circling an object in your field of view with your finger."Baidu is yet to announce a release date or marketing plans for Baidu Eye.Tis China's leading search engine company.回答a product that has more functions than Google Glasson September 3.回答FFEyecanscan objects with its small screen.回答company’s CEO Robin Li believes thatpeople will get used to searching by text.回答FF5. Baidu has already announced the release of Baidu Eye.回答（二）Tessera Multimedia was founded in 1997 and specializes in design and 回答A. developmentof web, multimedia and mobile applications.With headquarters in Thessaloniki, Tessera has developed business activities covering the whole Greece and has developed a significant partner network and a large customerA. bybase 回答investing in long-term relationships of trust and reliability.Our company has designed and successfully implemented a significant number ofC. projectscomplex software 回答in a wide range of has gained exceptional experience in designing web sites and portals, educational games, e-commerce applications and mobile apps.Tessera seeks to be always 回答B. up to datewith current trends and advancements in software technology, constantly investing in new technologies and human resources.The development department consists of 回答B. qualifiedstaff ensuring high quality, integrated the same time, our personnel is trained systematically in deploying new technologies, aiming that our productions are always on the cutting edge of technology.（三）阅读理解：这是客服人员帮助客服创建进入个人账户的场景，请在空格内填入字母将对话排序。