试卷2
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一、单选题(每题2 分,共16 分)1、传播学作为一门学科,诞生在【B 】A、中国B、美国C、德国D、日本2、报纸上的“读者来信”可以看作获取【D 】的一种形式。
A、熵B、噪音C、冗余信息D、反馈3、拉斯韦尔提出的传播模式是【B 】。
A、信息传送数学模式B、五W 模式C、两级传播模式D、议程设置模式4、赖特认为,传播的功能除了监测环境、联系社会、传承遗产之外,还有【D 】A、宣传B、规范C、教育D、娱乐5、《参考消息》的创办符合下列哪一条传播规律【C 】A、信息来源重要性B、诉诸情感C、防疫论D、休眠效应6、既能进行大众传播,又是人际传播重要工具的媒介是【D 】A、报刊B、广播C、电视D、互联网7、广告中使用动物形象来推销,符合宣传七种策略中的【B 】A、辱骂法B、转移法C、证词法D、平民百姓法8、德国学者伊丽莎白·诺纽曼提出的【D 】是一种强大效果理论。
A、教养理论B、知识沟假说C、第三者假说D、沉默的螺旋二、多选题(每题3 分,共24 分)1、下列哪些方法是量化/实证研究方法【A B C 】A、实地调查法B、内容分析法C、控制实验法D、哲学思辨2、人类传播的基本类型包括【A B C D 】A、自我传播B、人际传播C、组织传播D、大众传播3、人际传播的动机包括【A B C D 】A、认识自我B、建立人际关系C、控制周围环境D、进行情感沟通4、大众传播的功能包括【A B C D 】A、传播信息B、引导舆论C、教育大众D、提供娱乐5、下列传播活动哪些是在集权主义传播制度下进行的?【A D 】A、封建时代的传播活动B、当代西方资本主义国家的传播活动C、我国的新闻传播活动D、法西斯国家的传播活动6、麦克卢汉的理论包括【A B C 】A、媒介是人的延伸B、媒介即讯息C、冷媒介和热媒介D、媒介选择或然率公式7、下列对使用与满足理论的解说正确的是【A B C D 】A、这个理论从受众的角度出发来研究大众传播B、心理根源和社会根源引起了受众对信息的需求C、大众媒介通过不同形式来满足受众的信息需求D、最后导致需求的满足或其他(往往是非有意的)结果8、下列对创新与扩散论的解说正确的是【A B 】A、罗杰斯和休梅克的《创新的传播》是该理论的代表作B、它研究的是在社会中推广新技术、新知识的过程和效果C、用图表示的话,一项创新在社会中传播的过程大体上是一条直线D、比起人际传播来,大众媒介几乎没有任何传播效果三、名词解释(每题5 分,共分)1、信息人的精神创造物,是用以减少或者消除不确定性的任何事物。
2023年6月英语四级真题第2套Part I Writing (30 minutes)Directions:Suppose the student union of your university is organizing an online discussion on interpersonal relationships. You are to write an essay on ways to maintain a warm and friendly relationship with your classmates and on the benefits of such a relationship. You will have 30 minutes for the task. You should write at least 120 words but no more than 180 words.Part II Listening Comprehension (25 minutes)Section ADirections: In this section, you will hear three news reports. At the end of each news report, you will hear two or three questions. Both the news report and the questions will be spoken only once. After you hear a question, you must choose the best answer from the four choices marked A), B),C) and D). Then mark the corresponding letter on Answer Sheet 1 with a single line through the center.Questions 1 and 2 are based on the news report you have just heard.1. A) A man was bitten by a snake. C) A man kept a 4-foot snake as a pet.B) A man was taken to a hospital. D) A man fell off his toilet seat.2. A) Where the snake had been taken. C) How the snake was captured.B) Whether the snake was infected. D) Who owned the snake.Questions 3 and 4 are based on the news report you have just heard.3. A) Taking her trash out in fancy dresses. C) Sharing her photos with famous movie stars.B) Amusing herself by going to ball parties. D) Posting her daughter's photos on social media.4. A) To make herself popular. C) To please her daughter.B) To amuse people. D) To record her achievements.Questions 5 to 7 are based on the news report you have just heard.5. A) Eat as much as they want for $10. C) Have a meal even if they have no money.B) Have a chance of winning a $ 100 prize. D) Get a free meal after answering some questions.6. A) It was brought up by two staffers. C) It originated from a donation to her staff.B) It helped to popularize her restaurant. D) It was suggested by some of her customers.7. A) Fifty customers have offered donations. C) Many people have come to eat at the restaurant.B) More people have been giving than taking. D) Most staffers have received messages of kindness. Section BDirections:In this section, you will hear two long conversations. At the end of each conversation, you will hear four questions. Both the conversations and the questions will be spoken only once. After you hear a question, you must choose the best answer from the four choices marked A), B), C) and D). Then mark the corresponding letter on Answer Sheet 1 with a single line through the center.Questions 8 to 11 are based on the conversation you have just heard.8. A) He is a psychologist. C) He is a host for a TV program.B) He is a famous writer. D) He is a primary school teacher.9. A) Why social media accounts vanish without a trace.B) Why parents raise their children in different ways.C) Why people fail to respond to emails promptly.D) Why friends break off contact all of a sudden.10. A) They simply shut themselves down. C) They scream to get their parents back.B) They avoid showing their emotions. D) They attempt to ignore the whole situation.11. A) They may regard any difference as the end of a relationship.B) They are on better terms with friends and romantic partners.C) They try to express their feelings and thoughts effectively.D) They attach more value to their relationships with others.Questions 12 to 15 are based on the conversation you have just heard.12. A) Their price. C) Their quality.B) Their color. D) Their design.13. A) Jeans are a typical American garment.B). America makes the best-known brands of jeans.C) America has the best weaving tools in the world.D) Jeans are available in a greater variety in America.14. A) They are artificial. C) They are unique.B) They are natural. D) They are special.15. A) They are for casual wearing. C) They are much too pricey.B) They are popular with boys. D) They are worth the price.Section CDirections:In this section, you will hear three passages. At the end of each passage, you will hear three or four questions. Both the passages and the questions will be spoken only once. After you hear a question, you must choose the best answer from the four choices marked A), B), C) and D). Then mark the corresponding letter on Answer Sheet 1 with a single line through the center.Questions 16 to 18 are based on the passage you have just heard.16. A) He desires more in life. C) He feels as inspired as other audience members.B) He wants to see it again. D) He longs to become a superstar himself.17. A) It is rather unrealistic. C) It is somewhat complicated.B) It is extremely artistic. D) It is relatively predictable.18. A) They are biased against women. C) They are full of shootings.B) They are basically misleading. D) They are too simple.Questions 19 to 21 are based on the passage you have just heard.19. A) It can highlight leadership. C) It is a means to inspire creative thinking.B) It can help connect people. D) It is an intuitive way to solidify friendship.20. A) Allow them to recite data points. C) Enable them to remember the main idea.B) Make them more open to learning. D) Stimulate them to engage in discussions.21. A) Inspire listeners' imagination. C) Convey fundamental values.B) Enrich their own experience. D) Explain insightful ideas.Questions 22 to 25 are based on the passage you have just heard.22. A) Immigrants outnumber U.S.-born Americans.B) Immigrants have been contributing to the U.S.C) Another wave of immigrants is hitting the U.S.D) The number of immigrants to the U.S. is declining.23. A) More of them expect their children to succeed in business.B) They have fewer chances to be hired by U.S. companies.C) They have founded most Fortune 500 companies.D) More of them are successful business people.24. A) They have higher installment loan debt than native-born Americans.B) Nineteen percent of them borrow money from friends and family.C) Their level of debt is lower than that of native-born Americans.D) Thirty-four percent of them use credit for their daily purchases.25. A) Keep their traditional values and old habits. C) Borrow money from financial institutions.B) Find employment in competitive businesses. D) Collaborate with native-born Americans.Part III Reading Comprehension (40 minutes)Section ADirection s: In this section, there is a passage with ten blanks. You are required to select one word for each blank from a list of choices given in a word bank following the passage. Read the passage through carefully before making your choices. Each choice in the bank is identified by a letter. Please mark the corresponding letter for each item on Answer Sheet 2 with a single line through the centre. You may not use any of the words in the bank more than once.Morocco is responding to increasing energy demands by setting up one of the largest solar plants in the world.The Noor solar power station is ___26___ in the city of Ouarzazate and, once completed, will generate 580 million watts of electricity. The World Bank estimates it will serve 1.1 million people. It's ___27___ to be completed soon.Morocco's current energy comes ___28___ from imports. The nation hopes to get 50 percent of its energy from renewable sources by 2030. With demand for energy ___29___ at an annual rate of 7 percent, the new solar plant could be a ___30___ part of that goal."This makes Morocco a big ___31___ in the field of solar energy in the Arab region and the African continent. It could also be a forerunner for many other countries in the world that ___32___ on foreign imports of energy," said Ali Hajji, a solar energy specialist and engineering professor.Experts believe that the Middle East and North Africa have huge ___33___ for solar energy projects. This is partly because of adequate sunlight and partly because technology has become more ___34___ in the region."The last few years have seen a realization of ___35___ how competitive solar technologies can be," said Michael Taylor, a senior analyst at the International Renewable Energy Agency.A) affordable I) mostlyB) ancestor J) operatingC) crucial K) perhapsD) depend L) pioneerE) initial M) potentialF) insist N) risingG) just O) scheduledH) locatedSection BDirections:In this section, you are going to read a passage with ten statements attached to it. Each statement contains information given in one of the paragraphs. Identify the paragraph from which the information is derived. You may choose a paragraph more than once. Each paragraph is marked with a letter. Answer the questions by making the corresponding letter on Answer Sheet 2.New Formula One Chief Hopes to Grab Americans' AttentionA) For the past four decades, the leader of Formula One car racing, one of the biggest annual sporting seriesin the world, was Bernie Ecclestone, a former motorcycle parts dealer who built it into an international presence essentially on his own.B) A skilled backroom operator who speaks without a filter, Ecclestone said often that in his opinion, thesport was at its best when he was allowed to act as "a dictator.”C) Yet now the dictator is gone. After an American company, Liberty Media, acquired the Formula Onecompetition recently, Chase Carey—a former executive with Fox Broadcasting Company and DirecTV who by his own admission is not a fierce racing fan—was named to replace Ecclestone and to try to renovate the organization's management, reach and ambition.D) Among the goals, Carey said in an interview on Tuesday, is one that just about every global sport seemsinterested in chasing: increasing interest in the United States. "People have said we're going to "Americanize' it," Carey said. "And we're not going to do that totally. But realistically, there are some elements of Americanization that the sport could use."E) While Formula One commands enormous audiences throughout much of the world, many Americansports fans know it as that other motorsport, the one that is not Nascar (纳斯卡车赛). Formula One teams race far more technologically advanced vehicles around tracks all over the world-in magnificent events in places like Malaysia, Monaco, Singapore and the United Arab Emirates, and on tradition-rich tracks like Silverstone in England and Monza in Italy too.F) The series has an annual race in Austin, Texas. But within "a few years," Carey said, he plans to bringanother to a destination American city, like New York, Los Angeles, Miami or Las Vegas. Carey's ambitious plan is two-fold: first, change the business model of Formula One, which he said was a "one-man show" under Ecclestone that had a largely narrow vision when it came to negotiating partnership deals; and second, alter the way fans experience the sport, both in person and remotely, so that connections between the audience and people within the series are easier to make.G) Increased digital access for fans, a more behind-the-scenes experience for broadcast viewers andinnovation in areas like virtual reality-what is it like to speed around a track inside a Ferrari?-are among the possibilities. "The sport has clearly been underserved," Carey said. "It doesn't do anything digitally.There's no marketing. It doesn't tell any stories. The goal in this is to make the fans connect to the live experience as much as possible, and the tools you have to do that, we're not using at all."H) The larger question, though, is a familiar one: Is there room for Formula One in the ever-crowded sportslandscape of the United States? Opinions vary, particularly because viewing habits among consumers continue to evolve. John Bloom, a professor at Shippensburg University who has studied American sports history, said the biggest challenge for any sport trying to increase its presence in the United States was framing itself in a way that had lasting appeal. "Sports generally become popular in some way because they establish a narrative," Bloom said. "When I think of motorsports in the U.S., what we allthink of is Nascar, and the narrative of Nascar is sort of rural, white, working-class Americans, mostly in the South, connecting with the atmosphere of those races. That's the narrative. When I think of the narrative of Formula One, it's a very different kind of audience."I) That difference, Carey said, is significant. While some might immediately link Formula One to Nascar interms of American growth, Carey said Formula One's brand research had indicated there was very little crossover; rather, Formula One fans generally cite other so-called elite events, like Wimbledon or the Ryder Cup, as competitions they enjoy. "Other than they're both cars, the Nascar fan base is a very different fan base," Carey said. "It's a very regional fan base. Formula One is a global, famous brand of stars. These are machines that shock and awe you."J) Carey's background is in deal making and innovation. At Fox Broadcasting Company, he was a top advisor for years, known for his skill in helping to lead the launch of the company into sports, as well as the start of Fox News Channel. After going to DirecTV, he positioned the satellite provider as a mainstream option in millions of households.K) Now, after Liberty Media paid $4.4 billion to acquire Formula One, he is charged with making the investment pay off. "I think they can build Formula One in the U.S.," said Patrick Crakes, an executive at In Vivo Media Group who spent 25 years at Fox Broadcasting Company before leaving in 2016 as a senior manager at Fox Sports. "People don't work on their cars anymore. They don't want that connection anymore. It's about technology and pushing the limits. It's about speed, danger and risk. And Formula One has that more than any other racing series."L) That is what hooked Carey, and he said he thought his experience was not unusual. He recalled attending Formula One's Monaco race last year and being overwhelmed by the ceremony leading up to the event, the way the race charmed the city for days ahead of the start. In his mind, it felt like a Super Bowl (超级碗橄榄球赛).M) Then, on race day, he watched as the cars rocketed out of a tunnel and went screaming toward a tight turn with the city's harbor and the Mediterranean Sea in the background framing the scene. He was fascinated."You can't help but be awed," he said, "and I think that feeling can be translated to the viewer."N) He added: "The broader sport is a little too inward-looking, and we need to be more open. In some ways, I'm glad to be coming from the outside. The guys who are in the sport forever are sitting there saying: 'We can't do that. We can't do that because it's never been done that way.""36. Chase Carey believes greater use should be made of digital technology to make Formula One moreaccessible to its fans.37. Chase Carey was deeply impressed by the ceremony preceding last year's Monaco race.38. One of Chase Carey's goals is to make Formula One more appealing to Americans.39. A former motorbike parts dealer led Formula One for the past forty years.40. Chase Carey thought the audience of Formula One could be made to share his feeling about the race.41. Chase Carey used to serve as a top advisor for a major broadcasting company.42. Chase Carey intends to make connections easier between the audience and the Formula One racers.43. The new leader of Formula One admitted he was not super interested in car racing.44. People's opinions differ as to whether Formula One can be promoted in the U.S.45. Compared with other racing series, Formula One focuses more on speed and involves more danger.Section CDirections: There are 2 passages in this section. Each passage is followed by some questions or unfinished statements. For each of them there are four choices marked A),B),C)and D).You should decide on the best choice and mark the corresponding letter on Answer Sheet 2 with a single line through the centre. Passage OneQuestions 46 to 50 are based on the following passage.Supermarkets have long been suffering as one of the thinnest-margined businesses in existence and one of the least-looked-forward-to places to work or visit. For more than a decade, they have been under attack from e-commerce giants, blamed for making Americans fat, and accused of contributing to climate change.Supermarkets can technically be defined as giants housing 15,000 to 60,000 different products. The revolutionary idea of a self-service grocery, where people could hunt and gather food from aisles rather than asking a clerk to fetch items from behind a counter, first came about in America. There is some debate about which was the very first, but over the years a consensus has built around King Kullen Supermarket, founded in New York in 1930.For some 300 years, Americans had fed themselves from small stores and public markets. Shopping for food involved mud, noisy chickens, clouds of flies, nasty smells, bargaining, and getting short-changed. The supermarket imitated the Fordist factory, with its emphasis on efficiency and standardization, and reimagined it as a place to buy food. Supermarkets may not feel cutting-edge now, but they were a revolution in distribution at the time. They were such strange marvels that, on her first official state visit to the United States in 1957, Queen Elizabeth II insisted on an impromptu (即兴的)tour of a suburban-Maryland Giant Food.The typical supermarket layout has barely changed over the past 90 years. Most stores open with flowers, fruit and vegetables at the front as a breath of freshness to arouse our appetite. Meanwhile, they keep the milk, eggs, and other daily basics all the way back so you'll travel through as much of the store as possible, and be tempted along the way.In the early days, as the supermarket multiplied, so did our suspicion of it. We have long feared that this "revolution in distribution" uses corporate black magic on our appetite. The book The Hidden Persuaders, published in 1957, warned that supermarkets were putting women in a "hypnoidal trance (催眠恍惚状态)," causing them to wander aisles bumping into boxes and "picking things off shelves at random."46. What problem have supermarkets been facing?A) They are actually on the way to bankruptcy.C) They are forced to use e-commerce strategies.B) They have been losing customers and profits.D) They have difficulty adapting to climate change.47. What does the passage say about the idea of a self-service grocery?A) It was put forward by King Kullen. C) It has been under constant debate.B) It originated in the United States. D) It proves revolutionary even today.48. What did supermarkets do by adopting the Fordist factory approach?A) They modernized traditional groceries in many ways.B) They introduced cutting-edge layout of their stores.C) They improved the quality of the food they sold.D) They revolutionized the distribution of goods.49. What is the typical supermarket layout intended to do?A) Arouse customers' appetite to buy flowers, fruit and vegetables.B) Provide customers easy access to items they want to buy.C) Induce customers to make more unplanned purchases.D) Enable customers to have a more enjoyable shopping experience.50. What have people long feared about supermarkets?A) They use tricky strategies to promote their business.B) They are going to replace the local groceries entirely.C) They apply corporate black magic to the goods on display.D) They take advantage of the weaknesses of women shoppers.Passage TwoQuestions 51 to 55 are based on the following passage.The traditional school year, with three months of vacation every summer, was first implemented when America was an agricultural society and the summer months were needed for farm work. Since then, we've completely changed as a nation. Students no longer spend summers farming, but they aren't in school, either. The average American student receives 13 weeks off from school each calendar year-with about 11 of those during the summer. Few other countries have more than seven weeks off in a school calendar.With the U.S. lagging behind other countries in academics, it's time to consider year-round schooling. One benefit of this change is that students will not fall victim to the "summer slide," or the well-documented phenomenon where students forget some of the knowledge they have acquired when too much time is taken off from school. Decades of research shows that it can take from 8 to 13 weeks at the beginning of every school year for students to get back to where they were before the summer holiday.But year-round schooling isn't just about academics. Teachers and students experience a closer relationship in year-round schools than they do in traditional schools and, in the absence of any long-term break, students do not feel detached from the school environment. These closer bonds and greater attachment pay off. Research shows that students in year-round schools are more self-confident and feel more positive about their schooling experience.But don't kids need time to relax? Some childhood development experts believe that time off from school is vital to healthy development as kids are not designed to spend so much of their time inside classrooms and the summer break provides a perfect opportunity to get outside. The problem with this argument is that most children aren't playing outside or even spending time with other kids. While some children visit summer camps, most stay at home, watching TV or playing games on electronic devices, which hardly benefits them.The U.S. has changed from a farming economy to a knowledge- and innovation-based economy, so it makes sense for the school year to change as well.51. Why did America's traditional school year have a three-month summer vacation?A) Students needed to help with farm work.B) Students needed time to learn necessary farming skills.C) The agricultural society then attached less importance to academics.D) America lagged behind other countries in making a scientific school calendar.52. What benefit will year-round schooling bring students in addition to improving their learning?A) It will help them get back to where their lessons started.B) It will enable them to absorb what they have learned.C) It will familiarize them with the school environment.D) It will strengthen their relationship with teachers.53. What do some childhood development experts believe about the long summer vacation?A) It meets students' need to study on their own.B) It enables students to learn about the outside world.C) It satisfies students' desire to stay longer at home.D) It contributes to students' healthy growth.54. What is the argument against the experts' idea of a long summer vacation?A) It does little good to most students.B) It benefits few students playing outside.C) It leads students to neglect their studies.D) It makes students addicted to computer games.55. What does the author think of the traditional school year in the U.S. today?A) Well-grounded. C) Outdated.B) Culture-bound. D) Welcomed.Part IV Translation (30 minutes)Directions:For this part, you are allowed 30 minutes to translate a passage from Chinese into English. You should write your answer on Answer Sheet 2.改革开放40多年以来,中国政府对高等教育越来越重视,高等教育已经进入稳步发展阶段。
无人机驾驶员、机长模拟试题(二)1、近程无人机活动半径在______(1 分)A.小于15km B.15~50km C.200~800km2、近程无人机活动半径在______以内(1 分)A.15kmB.15-50kmC.50-200km3、按照飞行高度区分,以下属于高空飞行的是______(1 分)A.4500米(含)至9000米(含)B.8000米(含)至12000米(含)C.6000米(含)至12000米(含)4、飞控子系统必须具备如下功能:______(1 分)A.无人机姿态稳定与控制,无人机飞行管理,应急控制B.无人机飞行管理,与导航子系统协调完成航迹控制,信息收集与传递C.无人机起飞与着陆控制,无人机飞行管理,信息收集与传递5、地面控制站飞行参数综合显示的内容包括______(1 分)A.飞行与导航信息、数据链状态信息、设备状态信息、指令信息B.导航信息显示、航迹绘制显示以及地理信息的显示C.飞行与导航信息、数据链状信息、地图航迹显示6、______主要是由飞行操纵、任务载荷控制、数据链路控制和通信指挥库等组成,可完成对无人机机载任务载荷等的操纵控制。
(1 分)A.指挥处理中心B.无人机控制站C.载荷控制站7、指挥控制与______是无人机地面站的主要功能(1 分)A.导航B. 任务规划C. 飞行视角显示8、地面站地图航迹显示系统可为无人机驾驶员提供飞行器______等信息(1 分)A.飞行姿态B. 位置C. 飞控状态9、空域是航空器运行的环境,也是宝贵的国家资源。
国务院、中央军委十分重视我国民用航空交通管制的建设工作,目前正在推进空域管理改革,预计划分三类空域,为_____。
(1 分)A.管制空域、监视空域和报告空域B.管制空域、非管制空域和报告空域C.管制空域、非管制空域和特殊空域10、在一个划定的管制空域内,由______负责该空域内的航空器的空中交通管制(1 分)A 军航或民航的一个空中交通管制单位B 军航和民航的各一个空中交通管制单位C 军航的一个空中交通管制单位11、机场标高指着陆区______的标高。
古代汉语期末考试试卷(2)— 学年第一学期一 填空题(8%)1 《战国策》是一部___时代的史料汇编,流传到现在的本子是经过西汉___整理的。
对这部书,___时期___作过注。
2 《说文解字》是一部分析___说解___的专书,是___时期___所撰。
全书按___排列,共有___个部首。
3 汉代声训颇为流行,出现了一部声训专著,就是刘熙的___。
它为后世___ 理论的建立奠定了基础。
4 汉字形体的演变,经历了五个阶段,其中___、___、___是古文字,___、___是今文字。
二 语法分析题(22%)1 词类活用常见的词类活用,其类型有:A 名词用如动词B 形容词用如动词C 量词用如动词D 动词的使动用法E 名词的使动用法F 名词的意动用法G 形容词的使动用法H 形容词的意动用法I 对动用法J 为动用法K 名词作状语请找出下面句子中的活用现象,写在横线上并在它的后面填写序号。
1) 师还,馆于虞。
( ) 2) 越国以鄙远,君知其难也。
( ) 3) 以其无礼于晋,且贰于楚也。
( ) 4) 既东封郑,又欲肆其西封。
( )5) 遂置姜氏于城颍,而誓之曰。
( )6) 今君有区区之薛,不拊爱子其民,因而贾利之。
( ) 7) 邴夏御齐侯。
( ) 8) 孟尝君客我。
( )9) 晋侯饮赵盾酒。
( )( ) 10)蹇叔哭之,曰:“孟子,吾见师出而不见其入也。
” ( )2 指出下列句子的句型,并填写序号。
A 双宾语句B 宾语前置句C 判断句D 被动句E 谓语前置句 1)且君尝为晋君赐矣。
2)姜氏何厌之有?学院-------------------------------------- 班级--------------------------------------------- 姓名------------------------------------- 学号-------------------------------------3)郗克伤于矢。
1.______to the sunlight for too much time will do harm to your-skin.A.ExposedB.Being exposedC.Having exposedD.To expose2.Remind me_____the medicine tomorrow.A.of takingB.takingC.to takeD.take3.The bank is reported in the local newspaper _______in broad daylight yesterday.A.to be robbedB.robbedC.to have been robbedD.having been robbed4.The little boy came to life ______he took the medicine given by Doctor Snow.A.at onceB.immediatelyC.at lastD.shortly5.The doctor suggested that the girl______in order to lose weight.A.must not eat lessB.ought not to eat lessC.had better not eat lessD.not eat less6.So______was he in his work that he didn’t notice that it was raining hard.A.takenB.devotedC.absorbedD.interesting7.We alol feel it is Jack as well as his wife that______for their son’s bad performance at school.A.are to blameB.is to the blamedC.are to be blamedD.is to blame8.---Who is _____the patient?----Maybe his sister.A.taking careB.looking forC.joining inD.attending on9.I’m sure your suggestion will ______solving the problem.A.contribute toB.devote toC.lead toD.keep to10.That gas pipeline project,_______in July 2008 and ______in 2012, will be the country’s longest gas pipeline project in history.Astarting; completing B.atarted; to be completedC.to start ; completedD.starting; completed11.The discovery of the new evidence led to________.A.the thief having caughtB.catch the thiefC.the thief being caughtD.the thief to be caught12.Only when ______.A.did he arrive the meeting beganB.he arrived did the meeting beginC.did he arrive the meeting beginD.he arrived the meeting began13.No sooner ______themselves in their seats in the theatre _______the curtain went up.A.they have settled; beforeB.had they settled; thanC.have they settled; whenD.they had settled; than14.In no country other than Britain, it has been said,______experience four seasons in the course of a single day.A.people canB.you canC.can itD.can one15.______he met with the difficulty did he realize the importance of our help.A.Even thoughB.Never untilC.Only beforeD.Ever since16.Is the hotel_____offered you a job_____you stayed the first time you arrived here?A.which; whereB.the one; in whichC.where;thatD.the one that; which17.This is the book I bought yesterday,________I spent 8 yuan.A.on whichB.for whichC.in whichD.at which18.We finally bought several books written by Shakespeare,______is one.A.which of themB.which of whoseC.of which thisD.and of them19.Many buildings in the city need repairing,but the one______first is the library.A.repairedB.being repairedC.repairingD.to be repaired20.The doctor is skilled at treating heart trouble and never accepts any gift from his patients, so he has a very good_______.A.expectationB.reputationC.contributionD.civilization21.Gun control is a subject_______Americans have argued for a long time.A.of whichB.with whichC.about whichD.into which22.A narrow strait _____Europe from Africa.A.separatesB.divedesC.makesD.takes23.She is in ______with her employers over sick pay.petitionpositionC.conflictD.confirme and see me whenever_______.A.you are convenientB.you will be convenientC.it is convenient to youD.it will be conventient to you25.-----Is there any possibility _____you could pick me up at the airport?-----No problem.A.whenB.thatC.whetherD.what26.----I’m really hungry now.----That’s because you have left your lunch_______.A.untouchingB.to be untouchedC.untouchedD.being untouched27.On August 12,2009 Typhoon Morakot swept across Taiwan island,______a lot of villages_____.A.left; damagedB.leaving; damagingC.leaviing; damagedD.left; damaging28.______of danger in the street at night, she had to go home, with a friend______her.A.Warning; followingB.Having warned; followingC.Having been warned; followingD.Warned; followed29.Having sports is certainly good for you, but it remains_______whether you’ll do it.A.to seeB.to be seenC.seeingD.seen30.______is expected, according to the online survey, is that prices of houses will not go up any more.A.AsB.It .C.WhatD.Which31.If you have a job,_______yourself to it and finally you’ll succeed.A.do devoteB.don’t devoteC.devotingD.not devoting32.______is known to us all is that the 2008 Olympic Games will take place in Beijing.A.ItB.WhatC.AsD.Which33.To accomplish the task, you’d better ______the ideas not related to it and pay more attention to the point.A.sweep awayB.sweep asideC.break offD.sweep up34.Though ______money, his parents managed to send him to university.cekedcking ofckingcked in35.______with so many challenges, Y ang Guang, a blind young fellow, didn’t give up; he made great efforts to win success.A.FacingB.To faceC.FacedD.Face36.The student, if well _____, will pass the examination without much difficulty.A.preparingB.preparedC.to prepareD.ready37.______, Jane was able to buy her mother a lovely new watch.A.To saveB.SavingC.SavedD.Having saved38.________a lot of people needed medical help, I decided to be a volunteer worker.A.KnowB.KnownC.KnowingD.To know。
高等代数试卷(2)1. 填空题:(2×10=20)1.若向量组可由线性表示,且r>s,则线性。
2.数域P上所有n阶反对称矩阵构成的线性空间的维数是;3.设是线性空间V的两个子空间,则的充分必要条件是= ;4.数域P上的两个有限维线性空间同构的充分必要条件是。
5.设V是数域P上的n维线性空间,是V上一切线性变换所成的P上的线性空间,则dim(L(V))= 。
6.设是线性空间V的一组基,则由这个基到基的过度矩阵是。
7.令P n[x]表示一切次数不大于n的多项式连同零多项式组成的线性空间,,则关于基下的矩阵是。
8.设是n维欧氏空间V上的一个正交变换,且(单位变换),则是变换。
9.欧氏空间V上的对称变换的特征根都是数。
10.设是n维欧氏空间V的一组标准正交基,则它的度量矩阵是。
二.判断题(每题1分,计10分)1.设。
()2.两个等价的向量组一个线性无关,则另一个也线性无关。
()3.若,,且V中的任意一个向量都可由线性表示,则实数是V的组基。
()4.线性变换把线性无关的向量组变成线性无关的向量组。
()5.如果一个线性变换是单射,则它无零特征根。
()6.设是线性空间V上的一个线性变换,则的核与的象都是的不变子空间。
()7.如果W是欧氏空间的一个子空间,那么对V的内积来说,W也作成欧氏空间。
()8.设是欧氏空间V上的一个正交变换,则对于夹角等于的夹角。
()9.两个n元二次型(与(等价的充分必要条件是A与B合同。
()10.实二次型(正定的当且仅当A合同于单位矩阵。
()三、证明题(10×3=30)1.在一个欧氏空间里,对任意向量有不等式;且仅当线性相关时等式成立。
2.设V是数域P上的n维线性空间,是V的一组基,那么对V的任意n个向量有且仅有一个线性变换 σ 使得。
3.设,令V表示A的全体实系数多项式矩阵关于通常加法与数乘运算构成的线性空间;证明:dim(V)=3.四、计算题(15×2=30)1.设,求出一个正交矩阵U,使得是对角矩阵。
第1页(共6页)秘密★启用前2022年毕节市初中毕业生升学考试数 学考生注意:1.答题前,请务必将自己的姓名、准考证号填写在答题卡的规定位置.2.答题时,选择题使用2B 铅笔在答题卡上填涂,非选择题使用黑色字迹的笔在答题卡规定区域内作答,在试卷上作答无效.3.本试题共6页,满分150分,考试时间120分钟.一、选择题(本题15小题,每小题3分,共45分) 1.2的相反数是A .2B .2-C .12D .12-2.下列垃圾分类标识的图形中,既是中心对称图形又是轴对称图形的是A .B .C .D .3.截至2022年3月24日,携带“祝融号”火星车的“天问一号”环绕器在轨运行609天,距离地球277 000 000千米;277 000 000用科学记数法表示为A .277×106B .2.77×107C .2.8×108D .2.77×1084.计算()322x 的结果,正确的是A .58xB .56xC .66xD .68x5.如图,m ∥n ,其中∠1=40°,则∠2的度数为 A .130° B .140° C .150° D .160° 62cos 45-⨯︒的结果,正确的是AB.C. D.7.如果一个三角形的两边长分别为3,7,则第三边的长可以是A .3B .4C .7D .10第2页(共6页)8.在△ABC 中,用尺规作图,分别以点A 和C 为圆心,以大于12AC 的长为半径作弧,两弧相交于点M 和N .作直线MN 交AC 于点D ,交BC 于点E ,连接AE .则下列结论不一定正确的是 A .AB =AE B .AD =CD C .AE =CE D .∠ADE =∠CDE9.小明解分式方程121133xx x =-++的过程如下.解:去分母,得 32(33)x x =-+. ① 去括号,得 3233x x =-+. ② 移项、合并同类项,得 6x -=. ③ 化系数为1,得 6x =-.④ 以上步骤中,开始出错的一步是 A .① B .② C .③D .④10.如图,某地修建的一座建筑物的截面图的高BC =5 m ,坡面AB 的坡度为1AB 的长度为A .10 mB . mC .5 mD .m 11.中国清代算书《御制数理精蕴》中有这样一题:“马四匹、牛六头,共价四十八两(我国古代货币单位);马三匹、牛五头,共价三十八两.问马、牛各价几何?”设马每匹x 两,牛每头y 两,根据题意可列方程组为A .6448,5338x y x y +=⎧⎨+=⎩B .6438,5348x y x y +=⎧⎨+=⎩C .4648,3538x y x y +=⎧⎨+=⎩D .4638,3548x y x y +=⎧⎨+=⎩12.如图,一件扇形艺术品完全打开后, AB ,AC 夹角为120°,AB 的长为45 cm ,扇面BD 的长为30 cm ,则扇面的面积是 A .2375cm π B .2450cm πC .2600cm πD .2750cm π13.现代物流的高速发展,为乡村振兴提供了良好条件.某物流公司的汽车行驶30 km 后进入高速路,在高速路上匀速行驶一段时间后,再在乡村道路上行驶1 h 到达目的地.汽车行驶的时间x (单位:h )与行驶的路程y (单位:km)之间的关系如图所示.请结合图象,判断以下说法正确的是A .汽车在高速路上行驶了2.5 hB .汽车在高速路上行驶的路程是180 kmC .汽车在高速路上行驶的平均速度是72 km/h D .汽车在乡村道路上行驶的平均速度是40 km/hy第3页(共6页)14.在平面直角坐标系中,已知二次函数2y ax bx c =++(0a ≠)的图象如图所示,有下列5个结论: ①0abc >; ②20a b -=; ③930a b c ++>;④24b ac >; ⑤a c b +<.其中正确的有A .1个B .2个C .3个D .4个15.矩形纸片ABCD 中,E 为BC 的中点,连接AE ,将△ABE 沿AE 折叠得到△AFE ,连接CF .若AB =4,BC =6,则CF 的长是 A .3 B .175C .72D .185二、填空题(本题5小题,每小题5分,共25分) 16.分解因式:228=m -______.17.甲乙两人参加社会实践活动,随机选择“做环保志愿者”和“做交通引导员”两项中的一项,那么两人同时选择“做环保志愿者”的概率是______.18.如图,在Rt △ABC 中,∠BAC =90°,AB =3,BC =5,点P 为BC 边上任意一点,连接P A ,以P A ,PC 为邻边作平行四边形P AQC ,连接PQ ,则PQ 长度的最小值为______. 19.如图,在平面直角坐标系中,正方形ABCD 的顶点A ,B 分别在x 轴、y 轴上,对角线交于点E ,反比例函数ky x=(x >0,k >0)的图象经过点C ,E .若点A (3,0),则k 的值是______.18题图 19题图 20题图20.如图,在平面直角坐标系中,把一个点从原点开始向上平移1个单位,再向右平移1个单位,得到点A 1(1,1);把点A 1向上平移2个单位,再向左平移2个单位,得到点A 2(1-,3);把点A 2向下平移3个单位,再向左平移3个单位,得到点A 3(4-,0);把点A 3向下平移4个单位,再向右平移4个单位,得到点A 4(0,4-);…;按此做法进行下去,则点A 10的坐标为______.第4页(共6页)分数三、解答题(本题7小题,共80分) 21.(8分)先化简,再求值:2241442a a a a -⎛⎫÷- ⎪+++⎝⎭,其中2a .22.(8分)解不等式组()328131322x x x x --⎧⎪⎨-<-⎪⎩≤,,并把解集在数轴上表示出来.4321-3-2-123.(10分)某校在开展“网络安全知识教育周”期间,在八年级中随机抽取了20名学生分成甲、乙两组,每组各10人,进行“网络安全”现场知识竞赛.把甲、乙两组的成绩进行整理分析(满分100分,竞赛得分用x 表示: 90100x ≤≤为网络安全意识非常强,8090x <≤为网络安全意识强,80x <为网络安全意识一般). 收集整理的数据制成如下两幅统计图:甲组学生竞赛成绩统计图 乙组学生竞赛成绩统计图23题图123题图2分析数据:根据以上信息回答下列问题:(1)填空:a =______,b =______,c =______;(2)已知该校八年级有500人,估计八年级网络安全意识非常强的人数一共是多少? (3)现在准备从甲乙两组满分人数中抽取两名同学参加校际比赛,求抽取的两名同学恰好一人来自甲组,另一人来自乙组的概率.24.(12分)如图,在△ABC中,∠ACB=90°,D是AB边上一点,以BD为直径的⊙O与AC相切于点E,连接DE并延长交BC的延长线于点F.(1)求证:BF=BD;(2)若CF=1,tan∠EDB=2,求⊙O的直径.25.(12分)2022北京冬奥会期间,某网店直接从工厂购进A、B两款冰墩墩钥匙扣,进货价和销售价如下表:(注:利润=销售价 进货价)(1钥匙扣分别购进的件数;(2)第一次购进的冰墩墩钥匙扣售完后,该网店计划再次购进A、B两款冰墩墩钥匙扣共80件(进货价和销售价都不变),且进货总价不高于2 200元.应如何设计进货方案,才能获得最大销售利润,最大销售利润是多少?(3)冬奥会临近结束时,网店打算把B款钥匙扣调价销售.如果按照原价销售,平均每天可售4件.经调查发现,每降价1元,平均每天可多售2件,将销售价定为每件多少元时,才能使B款钥匙扣平均每天销售利润为90元?26.(14分)如图1,在四边形ABCD中,AC和BD相交于点O,AO=CO,∠BCA=∠CAD.(1)求证:四边形ABCD是平行四边形;(2)如图2,E,F,G分别是BO,CO,AD的中点,连接EF,GE,GF,若BD=2AB,BC=15,AC=16,求△EFG的周长.26题图1 26题图2第5页(共6页)第6页(共6页)27.(16分)如图,在平面直角坐标系中,抛物线2+y x bx c =-+与x 轴交于A ,B 两点,与y 轴交于点C ,顶点为D (2,1),抛物线的对称轴交直线BC 于点E . (1)求抛物线2+y x bx c =-+的表达式;(2)把上述抛物线沿它的对称轴向下平移,平移的距离为h (h >0),在平移过程中,该抛物线与直线BC 始终有交点,求h 的最大值;(3)M 是(1)中抛物线上一点,N 是直线BC 上一点.是否存在以点D ,E ,M ,N 为顶点的四边形是平行四边形?若存在,求出点N 的坐标;若不存在,请说明理由.。
试卷二一、单选题1.美国教育家布鲁纳强调学生在学习中的主动性和认知结构的重要性,认为教学的最终目的是促进学生对学科基本结构的掌握。
这种理论主张的学习方式是( A )A.发现学习B.认知结构学习C.意义学习D.接受学习2.最早对无意识现象进行深人研究的是( A )A.精神分析学派B.机能主义学派C.人本主义学派D.构造主义学派3.“吃不到葡萄说葡萄酸,得不到的东西就是不好的。
”这种心理防御方式称为( B )A.否认B.文饰B.投射 D.幻想4.下列情境中代表内在动机的情境是( D )A.课间休息时,小李回到教室做作业B.王老师对张华的单词测验成绩表示满意C.校长在全校大会上宣布三好学生名单D.陈英每天独自看几个小时电视5.在同一时间内能清楚把握对象的数量的是( A )A.注意的广度B.注意的分配C.注意的稳定性D.注意的转移6.“榜样学习”的教育效应最适宜的心理学解释理论是( d )A、强化说B、认知失调论C、从众说D、观察学习理论7.个体倾向于利用自己身体或内部参照作为信息加工依据的学习风格( b )A、场依存性B、场独立性C、冲动型D、沉思型8.先行组织者(用于接受学习)教学策略是给学习者提供( c )A、图表B、新知识C、引导性材料D、以上都对9.心理学家研究认为,态度的核心成分是(b )A、认知成分B、情感成分C、行为倾向成分D、认知与情感成分10.学过正方体、长方体等形体体积计算公式,再学习一般柱体的体积计算公式(V=SH),这种学习属于(A)。
A.上位学习B.下位学习C.并列结合学习D.发现学习11.在试误学习的过程中,在学习者对刺激情境做出特定的反应之后能够得到满意的结果时,其联结就会增强;而得到烦恼的结果时,其联结就会减弱。
桑代克将这一原理称为(A)。
A.效果律B.练习律C.准备律D.试误律12.动机冲突有多种形式,“鱼和熊掌不可兼得”的矛盾心理状态属于( A )A.双趋冲突B.双避冲突C.趋避冲突D.多重趋进冲突13.鲁班因茅草划破手这一事件引发思考而发明了锯,这类创造活动的心理影响机制主要是( D )A.功能固着B.迁移C.定势D.原型启发14.考试时,有些学生会因为老师站在旁边,一个字也写不出来。
一.单选题:1.决策选取最优方案的代价是(B )。
A.差量成本B.机会成本C.边际成本D.应付成本2.如果本期销售量比上期增加,则可断定按变动成本法计算的本期营业净利润(B )。
A.一定本期等于上期B.本期应当大于上期C.本期应当小于上期D.本期可能等于上期3.在其他因素不变的条件下,固定成本减少,保本点(B )。
A.升高B.降低C.不变D.不一定变动4.保本作业率与安全边际率之间的关系是(D )。
A.两者相等B.前者一般大于后者C.后者一般大于前者D.两者之和等于15.在管理会计学中,将“为实现管理会计目标,合理界定管理会计工作的时空泛围,统一管理会计操作方法和程序,组织管理会计工作不可缺少的前提条件”称为( A )。
A.管理会计假设B.管理会计原则C.管理会计术语D.管理会计概念6.如果完全成本法期末存货吸收的固定性制造费用大于期初存货释放的固定性制造费用,则完全成本法与变动成本法的营业净利润的差额( C )。
A.一定等于零B.可能等于零C.一定大于零D.一定小于零7.如果产品的单价与单位变动成本上升的百分率相同,其他因素不变,则保本销售量( B )。
A.上升B.下降C.不变D.不确定8.在不确定因素情况下,进行本量利分析时,各种有关因素的值是一个(B )。
A.概率值B.确定值C.分数值D.负数值9.销售量不变,保本点越高,则能实现的利润(A )。
A.越小B.不变C.越大D.不一定10.某企业全年发生的固定成本总额为600000元,预计当年实现目标利润300000元,产品销售单价500元/件,变动成本率为40%,则企业保本量是( B )。
A.1800件B.2000件C.4500件D.5000件11.已知某企业生产甲、乙两种产品,其单位贡献边际率分别为15%和20%,销售比重分别为40%和60%,则用加权平均法计算综合贡献边际率为( C )A .15% B.%C .18% D.20%12.如果某期按变动成本法计算的营业利润为6 000元,该期产量为3 000件,销售量为2 000件,期初存货为零,固定性制造费用总额为3 000元,则按完全成本法计算的营业利润为( D )元A.1 000 B.5 000 C.6 000 D.7 00013.责任会计的主体是(B )A.管理部门B.责任中心C.销售部门D.生产部门14.下列项目中,不属于现金流出项目的是(A )A.折旧费B.经营成本C.各项税款D.建设投资15.某企业的维修费是一项混合成本,在过去的12个月中,修理业务最高耗时30人工小时,发生修理费480元;修理业务最少时耗费12人工小时,发生修理费270元,则可分解出修理费用中固定成本为(C )A.110元B.120元C.130元D.150元16.普通年金是指(A )A.后付年金B.先付年金C.永续年金D.递延年金17.某企业只生产一种产品,单价6元,单位变动生产成本4元,单位销售和管理变动成本元,销量500件,则其产品贡献边际为(B )元A.650 B.750C.850 D.95018.某产品保本作业率60%,边际贡献率35%,则其销售利润率等于(A )。
试卷:食品安全法律法规考试分数:100.0考试时间:50分钟一、单项选择(每题2.0分):1.以下说法错误的是_B__。
A.县级以上食品药品监督管理部门接到咨询、投诉、举报,对属于本部门管辖的,应当受理,并及时进行核实、处理、答复。
B.县级以上食品药品监督管理部门接到咨询、投诉、举报,对不属于本部门管辖的,应当电话通知并移交有管辖权的部门处理。
C.县级以上食品药品监督管理部门接到咨询、投诉、举报,对不属于本部门管辖的,应当书面通知并移交有管辖权的部门处理。
D.食品药品监督管理部门可以聘请社会监督员,协助开展餐饮服务食品安全监督。
2.餐饮服务食品安全监管部门选派监督员的人数至少是__B __。
A.1B.2C.3D.43.食品、食品添加剂和食品相关产品采购记录应当如实记录__D_。
A.产品的名称、规格、数量B.产品的生产批号、保质期C.供应单位名称及联系方式、进货日期D.以上都是(第36、39条)4.《餐饮服务许可管理办法》不适用于_B_。
A.从事餐饮服务的单位和个人B.食品摊贩(第2条)C.从事餐饮服务的个人D.餐饮服务提供者5.食品库房中,应与食品分开设置的是_B_。
A.不会导致食品污染的食品容器B.会导致食品污染的非食品(第(六)1条)C.不会导致食品污染的包装材料D.不会导致食品污染的工用具6.对因__C___而被召回的食品,食品生产者在采取补救措施且能保证食品安全的情况下可以继续销售;销售时应当向消费者明示补救措施。
A.没有出厂检验合格B.超过保质期C.标签、标识或者说明书不符合食品安全标准(第33条)D.添加了非食品原料7.违反《食品安全法》的有关规定,最高可处违法货值金额__C___倍罚款。
A.3B.5C.10(第84、85条)D.208.奶油类原料应__D___。
A.常温存放B.低温存放C.放在阴凉通风处D.以上都不对(第28(四)条)9.食品用工具容器最佳质材___A__。
A.不锈钢(第十五6条)B.木制品C.竹制品D.铁制品10.食品处理区应保持良好通风,及时排除潮湿和污浊的空气。
大学物理2试卷二一、填空题(共21分)1(本题3分)两种不同的理想气体,若它们的最概然速率相等,则它们的 (A) 平均速率相等,方均根速率相等. (B) 平均速率相等,方均根速率不相等. (C) 平均速率不相等,方均根速率相等.(D) 平均速率不相等,方均根速率不相等. [ ] 2(本题3分)一定量的理想气体,在温度不变的条件下,当体积增大时,分子的平均碰撞频率Z 和平均自由程λ的变化情况是:(A) Z 减小而λ不变. (B)Z 减小而λ增大.(C) Z 增大而λ减小. (D)Z 不变而λ增大. [ ]3(本题3分)一辆汽车以25 m/s 的速度远离一辆静止的正在鸣笛的机车.机车汽笛的频率为600 Hz ,汽车中的乘客听到机车鸣笛声音的频率是(已知空气中的声速为330 m/s ) (A) 550 Hz . (B) 645 Hz .(C) 555 Hz . (D) 649 Hz . [ ] 4(本题3分)如图,用单色光垂直照射在观察牛顿环的装置上.当平凸透镜垂直向上缓慢平移而远离平面玻璃时,可以观察到这些环状干涉条纹(A) 向右平移. (B) 向中心收缩. (C) 向外扩张. (D) 静止不动.(E) 向左平移. [ ]5(本题3分)一束自然光自空气射向一块平板玻璃(如图),设入射角等于布儒斯特角i 0,则在界面2的反射光(A) 是自然光.(B) 是线偏振光且光矢量的振动方向垂直于入射面.(C) 是线偏振光且光矢量的振动方向平行于入射面.(D) 是部分偏振光. [ ]6(本题3分)用频率为的单色光照射某种金属时,逸出光电子的最大动能为E K ;若改用频率为2的单色光照射此种金属时,则逸出光电子的最大动能为:(A) 2 E K . . (B) 2h - E K .(C) h - E K . (D) h + E K . [ ] 7(本题3分)不确定关系式h p x x ≥⋅∆∆表示在x 方向上(A) 粒子位置不能准确确定. (B) 粒子动量不能准确确定. (C) 粒子位置和动量都不能准确确定.(D) 粒子位置和动量不能同时准确确定. [ ]空气单色光i 012二、填空题(共19分)8(本题3分)1 mol 氧气(视为刚性双原子分子的理想气体)贮于一氧气瓶中,温度为27℃,这瓶氧气的内能为________________J ;分子的平均平动动能为____________J;分子的平均总动能为_____________________J.9(本题4分)现有两条气体分子速率分布曲线(1)和(2),如图所示. 若两条曲线分别表示同一种气体处于不同的温度下的速率分布,则曲线_____表示气体的温度较高. 若两条曲线分别表示同一温度下的氢气和氧气的速率分布,则曲线_____表示的是氧气的速率分布. 10(本题3分)一个质点同时参与两个在同一直线上的简谐振动,其表达式分别为)612cos(10421π+⨯=-t x , )652cos(10322π-⨯=-t x (SI)则其合成振动的振幅为___________,初相为_______________. 11(本题3分)在真空中沿着z 轴的正方向传播的平面电磁波,O 点处电场强度为)6/2cos(900π+π=t E x ν,则O 点处磁场强度为_______________________.(真空介电常量 0 = ×10-12 F/m ,真空磁导率 0 =4×10-7 H/m ) 12(本题3分)一束光垂直入射在偏振片P 上,以入射光线为轴转动P ,观察通过P 的光 强的变化过程.若入射光是__________________光,则将看到光强不变;若入 射光是__________________,则将看到明暗交替变化,有时出现全暗;若入射光 是_________________,则将看到明暗交替变化,但不出现全暗. 13(本题3分)根据氢原子理论,若大量氢原子处于主量子数n = 5的激发态,则跃迁辐射的谱线可以有________条,其中属于巴耳末系的谱线有______条.三、计算题(共60分)14(本题10分)0.32kg 的氧气作如图所示的ABCDA 循环,设212V V =,1300K T =,2200K T =,求循环效率。
期末复习二一、选择题(共10小题,每小题4分,共40分,在每小题列出的四个选项中,选出符合题目要求的一项)1.已知a R ∈,()13ai i i +=+,(i 为虚数单位),则=a ()A .1- B.1C.3- D.32.已知直线20l y ++=,下列说法中正确的是()A.直线l 的倾斜角为120︒B.(是直线l 的一个方向向量C.直线lD.)1-是直线l 的一个法向量3.的是()A.22142x y += B.221x y -= C.2213y x -= D.24y x=4.设a R ∈,则“a =1”是“直线ax+y-1=0与直线x+ay+1=0平行”的A.充分不必要条件 B.必要不充分条件C.充分必要条件D.既不充分也不必要条件,5.若直线l :0x y m --=经过抛物线28y x =的焦点,且与抛物线交于A ,B 两点,则下列说法中错误的是()A.抛物线的焦点为()2,0B.2m =C.抛物线的准线为4x =- D.16AB =6.下列关于圆C :22(1)4x y +-=的说法中正确的个数为()①圆C 的圆心为(0,1)C ,半径为2②直线l :3410x y -+=与圆C 相交③圆C 与圆1C :22(1)(2)9x y ++-=相交④过点2)作圆C 50y --=A.1B.2C.3D.47.公元前4世纪,古希腊数学家梅内克缪斯利用垂直于母线的平面去截顶角分别为锐角、钝角和直角的圆锥,发现了三种圆锥曲线.之后,数学家亚理士塔欧、欧几里得、阿波罗尼斯等都对圆锥曲线进行了深入的研究.直到3世纪末,帕普斯才在其《数学汇编》中首次证明:与定点和定直线的距离成定比的点的轨迹是圆锥曲线,定比小于、大于和等于1分别对应椭圆、双曲线和抛物线.已知,A B 是平面内两个定点,且|AB |=4,则下列关于轨迹的说法中错误的是()A.到,A B 两点距离相等的点的轨迹是直线B.到,A B 两点距离之比等于2的点的轨迹是圆C.到,A B 两点距离之和等于5的点的轨迹是椭圆D.到,A B 两点距离之差等于3的点的轨迹是双曲线8.已知正方体ABCD ﹣A 1B 1C 1D 1的棱长为1,若点P 满足1311534AP AB AD AA =++,则点P 到直线AB 的距离为()A.25144 B.512C.1320D.159.已知椭圆1C :222116x y m +=和双曲线2C :22214x yn-=有公共的焦点F 1(−3,0),F 2(3,0),点P 是C 1与C 2在第一象限内的交点,则下列说法中错误的个数为()①椭圆的短轴长为;②双曲线的虚轴长为③双曲线C 2的离心率恰好为椭圆C 1离心率的两倍;④ PF 1F 2是一个以PF 2为底的等腰三角形.A.0B.1C.2D.310.已知动圆C 经过点1(0)F ,,并且与直线1y =-相切,若直线50l y -+=与圆C 最多有一个公共点,则圆C 的面积()A.有最小值为16π9B.有最大值为16π9C.有最小值为16πD.有最大值为16π二、填空题(共6小题,每小题4分,共24分)11.若直线l 与直线2x-y-1=0垂直,且不过第一象限,试写出一个直线l 的方程:________.12.与双曲线224312y x -=有相同焦点,且长轴长为6的椭圆标准方程为_________.13.已知椭圆C :22221x y a b+=(0a b >>)中,1F ,2F 为椭圆的左、右焦点,1B ,2B 为椭圆的上、下顶点,若四边形1122F B F B 是一个正方形,则椭圆的离心率为__________.14.过点()2,5作圆22:(1)4C x y +-=的切线,则切线方程为__________.15.已知O 为坐标原点,抛物线的焦点F 在x 轴上,且过点(1,2)-,P 为抛物线上一点,||3PF =,则抛物线的标准方程为___________,OPF △的面积为_____________.16.若点()2,0到直线l 的距离小于1,则在下列曲线中:①28y x =;②()2234x y -+=;③22195x y +=;④2213y x -=;与直线l 一定有公共点的曲线的序号是_________.(写出你认为正确的所有序号)三、解答题(共3题,共36分,解答应写出文字说明,演算步骤或证明过程)17.如图,在四棱锥P ABCD -中,底面ABCD 为正方形,PA ⊥平面ABCD ,,M N 分别为棱,PD BC 的中点,2PA AB ==.(1)求证://MN 平面PAB ;(2)求直线MN 与平面PCD 所成角的正弦值.18.已知椭圆()2222:10x y C a b a b+=>>的左、右顶点分别为,A B ,且AB 4=,离心率为12,O 为坐标原点.(1)求椭圆C 的方程;(2)设P 是椭圆C 上不同于,A B 的一点,直线,PA PB 与直线4x =分别交于点,M N .证明:以线段MN 为直径作圆被x 轴截得的弦长为定值,并求出这个定值.19.已知抛物线2:4C y x =,O 为坐标原点,过焦点F 的直线l 与抛物线C 交于不同两点,A B .(1)记AFO V 和BFO V 的面积分别为12,S S ,若212S S =,求直线l 的方程;(2)判断在x 轴上是否存在点M ,使得四边形OAMB 为矩形,并说明理由.期末复习二一、选择题(共10小题,每小题4分,共40分,在每小题列出的四个选项中,选出符合题目要求的一项)1.已知a R ∈,()13ai i i +=+,(i 为虚数单位),则=a ()A.1-B.1C.3- D.3C【分析】首先计算左侧的结果,然后结合复数相等的充分必要条件即可求得实数a 的值.【详解】()213ai i i ai i a a i i +=-=-+=++=,利用复数相等的充分必要条件可得:3,3a a -=∴=-.故选:C.2.已知直线20l y ++=,下列说法中正确的是()A.直线l 的倾斜角为120︒B.(是直线l 的一个方向向量C.直线lD.)1-是直线l 的一个法向量A【分析】先根据方程得斜率,进而得到直线的倾斜角,以及方向向量和方法向量,从而判断各选项.【详解】因为直线:20l y ++=,所以斜率k =120︒,故A 正确,C 不正确;因为直线l 经过点()0,2A -,()B ,所以直线l 的一个方向向量为()AB =,因向量(与()AB =不共线,故(不是直线l 的一个方向向量,故B 不正确;又因为)13360AB -⋅=--=-≠,所以)1-不是直线l 的一个法向量,故D 不正确.故选:A.3.的是()A.22142x y += B.221x y -= C.2213y x -= D.24y x=B【分析】根据标准方程逐个求出离心率,即可得到.【详解】对于A :22142x y +=中2,a b c ===22c e a ==,所以A 错误;对于B :221x y -=中1,1,a b c ====,则ce a==B 正确;对于C :2213y x -=中1,2a b c ===,则2c e a ==,所以C 错误;对于D :24y x =中1e =,所以D 错误;故选:B4.设a R ∈,则“a =1”是“直线ax+y-1=0与直线x+ay+1=0平行”的A.充分不必要条件 B.必要不充分条件C.充分必要条件 D.既不充分也不必要条件,C【详解】若直线ax+y-1=0与直线x+ay+1=0平行,则21a =,且11a-≠解得1a =故选C点睛:这是一道关于充分条件和必要条件判断的题目.考查的主要是充分条件,必要条件,熟练掌握掌握充分条件和必要条件的判定方法.本题中,利用直线平行的条件是解决问题的关键.5.若直线l :0x y m --=经过抛物线28y x =的焦点,且与抛物线交于A ,B 两点,则下列说法中错误的是()A.抛物线的焦点为()2,0B.2m =C.抛物线的准线为4x =-D.16AB =C【分析】求出抛物线的焦点坐标、准线方程,将焦点坐标代入直线方程求出实数m ,将直线方程与抛物线方程联立,求出焦点弦长,依次判断选项即可.【详解】设抛物线方程为22y px =(0p >),则焦点坐标为,02p F ⎛⎫ ⎪⎝⎭,准线方程为2px =-,∵抛物线方程为28y x =,∴4p =,22p=,∴抛物线的焦点坐标()2,0F ,准线方程为2x =-,将焦点()2,0F 代入直线l 的方程:0x y m --=得200m --=,∴2m =,∴直线l 的方程为20x y --=,设直线l 与抛物线28y x =两交点坐标为()11,A x y ,()22,B x y ,点A ,B 到准线的距离分别为A d ,B d ,由2820y x x y ⎧=⎨--=⎩消去y ,化简得21240x x -+=(0∆>),∴1212x x +=,∴由抛物线的定义,12A p AF d x ==+,22B p BF d x ==+,∴1212416AB AF BF x x p =+=++=+=.对于A ,抛物线的焦点坐标()2,0F ,选项A 正确;对于B ,实数m 的值为2m =,选项B 正确;对于C ,抛物线的准线方程为2x =-,选项C 错误;对于D ,弦长16AB =,选项D 正确,故以上说法中,错误的是C 选项.故选:C.6.下列关于圆C :22(1)4x y +-=的说法中正确的个数为()①圆C 的圆心为(0,1)C ,半径为2②直线l :3410x y -+=与圆C 相交③圆C 与圆1C :22(1)(2)9x y ++-=相交④过点2)作圆C 50y --=A.1 B.2C.3D.4C【分析】对于①,根据圆的标准方程求出圆心坐标和半径,可知①正确;对于②,根据圆心到直线的距离小于半径,可知②正确;对于③,根据圆心距与两圆半径之间的关系,可知③正确;对于④,点2)在圆C ,可知点2)在圆C ,求出切线的斜率,根据点斜式可求出切线方程,可知④不正确.【详解】对于①,由22(1)4x y +-=可知,圆心为(0,1)C ,半径为2,故①正确;对于②,圆心(0,1)C 到直线3410x y -+=的距离35d ==2<,所以直线l :3410x y -+=与圆C 相交,故②正确;对于③,圆1C :22(1)(2)9x y ++-=的圆心1(1,2)C -,半径为3,因为圆心距1||CC ==,且3232-<<+,所以圆C 与圆1C :22(1)(2)9x y ++-=相交,故③正确;对于④,因为点2)在圆C :22(1)4x y +-=上,所以点2)为切点,所以切点与圆心C3=,所以切线的斜率为,所以切线方程为:2y x -=-50y +-=,故④不正确.故选:C7.公元前4世纪,古希腊数学家梅内克缪斯利用垂直于母线的平面去截顶角分别为锐角、钝角和直角的圆锥,发现了三种圆锥曲线.之后,数学家亚理士塔欧、欧几里得、阿波罗尼斯等都对圆锥曲线进行了深入的研究.直到3世纪末,帕普斯才在其《数学汇编》中首次证明:与定点和定直线的距离成定比的点的轨迹是圆锥曲线,定比小于、大于和等于1分别对应椭圆、双曲线和抛物线.已知,A B 是平面内两个定点,且|AB |=4,则下列关于轨迹的说法中错误的是()A.到,A B 两点距离相等的点的轨迹是直线B.到,A B 两点距离之比等于2的点的轨迹是圆C.到,A B 两点距离之和等于5的点的轨迹是椭圆D.到,A B 两点距离之差等于3的点的轨迹是双曲线D【分析】判断到,A B 两点距离相等的点的轨迹是,A B 连线的垂直平分线,判断A;建立平面直角坐标系,求出动点的轨迹方程,可判断B;根据椭圆以及双曲线的定义可判断C,D .【详解】对于A ,到,A B 两点距离相等的点的轨迹是,A B 连线的垂直平分线,正确;对于B ,以AB 为x 轴,AB 的中垂线为y 轴建立平面直角坐标系,则()()2,0,2,0A B -,设动点(,)P x y ,由题意知||2||PA PB =,2=,化简为221064(39x y -+=,即此时点的轨迹为圆,B 正确;对于C ,不妨设动点P 到,A B 两点距离之和等于5,即5PA PB +=,由于54>,故到,A B 两点距离之和等于5的点的轨迹是以,A B 为焦点的椭圆,C 正确;对于D ,设动点P 到,A B 两点距离之差等于3,即||||3-=PA PB ,由于34<,故到,A B 两点距离之差等于3的点的轨迹是双曲线靠近B 侧的一支,D 错误,故选:D8.已知正方体ABCD ﹣A 1B 1C 1D 1的棱长为1,若点P 满足1311534AP AB AD AA =++,则点P 到直线AB 的距离为()A.25144 B.512C.1320D.10515B【分析】过P 作PM ⊥平面ABCD 于点M ,过M 作NM AB ⊥于点N ,连接PN ,则PN 即为所求,【详解】解:如图,过P 作PM ⊥平面ABCD 于点M ,过M 作NM AB ⊥于点N ,连接PN ,则PN 即为所求,因为满足1311534AP AB AD AA =++,所以35AN =,13MN =,14MP =,所以512PN ==,故选:B .【点睛】本题考查了求点到直线的距离的方法,属于基础题.9.已知椭圆1C :222116x y m +=和双曲线2C :22214x yn-=有公共的焦点F 1(−3,0),F 2(3,0),点P 是C 1与C 2在第一象限内的交点,则下列说法中错误的个数为()①椭圆的短轴长为;②双曲线的虚轴长为③双曲线C 2的离心率恰好为椭圆C 1离心率的两倍;④ PF 1F 2是一个以PF 2为底的等腰三角形.A.0 B.1C.2D.3A【分析】根据椭圆1C :222116x y m +=和双曲线2C :22214x yn-=有公共的焦点F 1(−3,0),F 2(3,0),求得m ,n ,再逐项判断.【详解】解:因为椭圆1C :222116x y m +=和双曲线2C :22214x yn-=有公共的焦点F 1(−3,0),F 2(3,0),所以2216949m n ⎧-=⎨+=⎩,解得m n ⎧=⎪⎨=⎪⎩则①椭圆的短轴长为,故正确;②双曲线的虚轴长为③双曲线C 2的离心率32e =,椭圆C 1离心率的34e =,故正确;④由22221167145x y x y ⎧+=⎪⎪⎨⎪-=⎪⎩,解得833P ⎛ ⎝⎭,则16PF =,211222,6PF a PF F F =-==,所以 PF 1F 2是一个以PF 2为底的等腰三角形,故正确.故选:A10.已知动圆C 经过点1(0)F ,,并且与直线1y =-相切,若直线50l y -+=与圆C 最多有一个公共点,则圆C 的面积()A.有最小值为16π9B.有最大值为16π9C.有最小值为16πD.有最大值为16πD【分析】已知直线:50l y -+=与圆C 最多有一个公共点,则直线l 与圆相切或相离,而圆C 经过点1(0)F ,,并且与直线1y =-相切,则直线l 与圆相切时圆最大,直线l 与圆相离时圆最小,数形结合求出半径即可得到圆C 的面积.【详解】解:已知直线50l y -+=与圆C 最多有一个公共点,则直线l 与圆相切或相离,当直线l 与圆相离时圆最小,满足经过点1(0)F ,,并且与直线1y =-相切的圆如图所示,此时以原点O 为圆心,1为半径,圆C 的面积2min π1πS =⋅=,故A ,C 选项错误;当直线l 与圆相切时圆最大,满足经过点1(0)F ,,并且与直线1y =-相切的圆如图所示,此时直线l 与直线1y =-为圆2C 的公切线,则圆心需在两直线所成角的角平分线上,因为直线l 60︒,所以角平分线的倾斜角为30︒,斜率为33,联立501y y -+==-⎪⎩,可得63,13A ⎛⎫-- ⎪ ⎪⎝⎭所以角平分线的方程为133y x ⎛⎫+=+ ⎪ ⎪⎝⎭,即13y x =+,恰好点1(0)F ,在角平分线上,则222r AF r =+,所以222224r r r r ===+,解得24r =,圆C 的面积2max π416πS =⋅=,故B 选项错误;故选:D.二、填空题(共6小题,每小题4分,共24分)11.若直线l 与直线2x-y-1=0垂直,且不过第一象限,试写出一个直线l 的方程:________.112y x =--(答案不唯一)【详解】由直线l 与直线210x y --=垂直,设直线l 的方程为12y x c =-+∵直线l 不经过第一象限∴0c ≤∴可令1c =-,即直线l 的方程为112y x =--故答案为112y x =--(答案不唯一).12.与双曲线224312y x -=有相同焦点,且长轴长为6的椭圆标准方程为_________.22129x y +=【分析】双曲线化为标准形式,求出焦点,即可由共焦点进一步求出椭圆短半轴,即可求得标准方程.【详解】224312y x -=即22134y x -=,焦点为(0,,椭圆长轴26a =,即3a =,故短半轴b ==22129x y +=.故答案为:22129x y +=.13.已知椭圆C :22221x y a b+=(0a b >>)中,1F ,2F 为椭圆的左、右焦点,1B ,2B 为椭圆的上、下顶点,若四边形1122F B F B 是一个正方形,则椭圆的离心率为__________.22【分析】四边形1122F B F B 是个正方形,则其对角线12F F 与12B B 相等,即22c b =,由此结合a ,b ,c 的关系,即可求出离心率.【详解】∵四边形1122F B F B 是一个正方形,∴正方形1122F B F B 的对角线相等,1212F F B B =,∵焦距122F F c =,短轴长122B B b =,∴22c b =即c b =,∴a ===,∴离心率22c e a ===.故答案为:2.14.过点()2,5作圆22:(1)4C x y +-=的切线,则切线方程为__________.2x =或34140x y -+=【分析】当斜率不存在时,检验即可;当斜率存在时,设出直线,利用圆心到直线的距离等于半径列方程求解即可.【详解】圆22:(1)4C x y +-=的圆心为()0,1,半径2r =过点()2,5的直线,当斜率不存在时,直线方程为2x =,符合与圆C 相切;当斜率存在时,设直线方程为()25y k x =-+,即250kx y k --+=,2=,解得34k =,此时直线方程为34140x y -+=.故答案为:2x =或34140x y -+=.15.已知O 为坐标原点,抛物线的焦点F 在x 轴上,且过点(1,2)-,P 为抛物线上一点,||3PF =,则抛物线的标准方程为___________,OPF △的面积为_____________.①.24y x =②.【分析】设抛物线方程为22y ax =(0)a ≠,将点(1,2)-代入求出a ,可得抛物线的标准方程;设00(,)P x y ,根据||3PF =以及抛物线的定义求出0x 和0y ,根据三角形的面积公式可求出结果.【详解】依题意,设抛物线方程为22y ax =(0)a ≠,因为抛物线过点(1,2)-,所以2(2)2a -=,所以2a =,所以抛物线的标准方程为:24y x =.由24y x =可知,准线方程为:=1x -,设00(,)P x y ,则0||1PF x =+,因为||3PF =,所以013x +=,即02x =.所以2004428y x ==⨯=,所以0||y =,所以OPF △的面积为:011||||122OF y ⋅=⨯⨯=.故答案为:24y x =.16.若点()2,0到直线l 的距离小于1,则在下列曲线中:①28y x =;②()2234x y -+=;③22195x y +=;④2213y x -=;与直线l 一定有公共点的曲线的序号是_________.(写出你认为正确的所有序号)①②③④【分析】将问题转化为直线l 必经过圆()2221x y -+=的内的点,分别作出每个选项与圆()2221x y -+=的图象,根据包含关系可确定结果.【详解】若点()2,0到直线l 的距离小于1,则直线l 必经过以()2,0为圆心,1为半径的圆的内部,即直线l 必经过圆()2221x y -+=的内的点;对于①,作出28y x =与()2221x y -+=图象如下图所示,则过圆()2221x y -+=内的点的所有直线与28y x =都有交点,①正确;对于②,作出()2234x y -+=与()2221x y -+=图象如下图所示,则过圆()2221x y -+=内的点的所有直线与()2234x y -+=都有交点,②正确;对于③,作出22195x y +=与()2221x y -+=图象如下图所示,则过圆()2221x y -+=内的点的所有直线与22195x y +=都有交点,③正确;对于④,作出2213y x -=与()2221x y -+=图象如下图所示,则过圆()2221x y -+=内的点的所有直线与2213y x -=都有交点,④正确.故答案为:①②③④.【点睛】关键点点睛:本题考查圆锥曲线中各种曲线图象之间的关系,解题关键是能够将问题转化为经过圆内部的点的直线与曲线永远有公共点,从而根据曲线方程作出图象,根据图象包含关系来确定结果.三、解答题(共3题,共36分,解答应写出文字说明,演算步骤或证明过程)17.如图,在四棱锥P ABCD -中,底面ABCD 为正方形,PA ⊥平面ABCD ,,M N 分别为棱,PD BC 的中点,2PA AB ==.(1)求证://MN 平面PAB ;(2)求直线MN 与平面PCD 所成角的正弦值.(1)证明见解析;(2)1010.【分析】(1)证明线面平行,用线面平行的判定定理,在面PAB 内找一条直线与MN 平行;(2)建立空间直角坐标系,利用向量法求线面角.【详解】(1)在四棱锥P ABCD -中,取PA 的中点E ,连接EB 、EM ,因为M 是PD 的中点,所以EM AD ,且12EM AD =.又因为底面ABCD 是正方形,N 是BC 的中点,所以BN AD ∥,且12=BN AD ,所以EM BN ∥且=EM BN ,所以四边形MNBE 是平行四边形.所以MN BE ∥.由于EB ⊂平面PAB ,MN ⊄平面PAB ,所以//MN 平面PAB .(2)因为底面ABCD 是正方形,所以AB ⊥AD .又因为PA ⊥平面ABCD ,所以可以以点A 为坐标原点,AB 、AD 、AP 分别为x 、y 、z 轴,如图建立空间直角坐标系,则(0,0,0)A ,(2,2,0)C ,(0,2,0)D ,(0,0,2)P ,(0,1,1)M ,(2,1,0)N .(2,2,2),(2,0,0)PC CD →→=-=-,设平面PCD 的法向量为(,,)m x y z =,有:0,0,m PC m CD ⎧⋅=⎨⋅=⎩即0,0,x y z x +-=⎧⎨=⎩,令1y =,则=1z ,所以(0,1,1)m = .(2,0,1)MN =- ,设直线MN 与平面PCD 所成角为θ,有:sin cos ,MN m θ= =MN m MN m⋅⋅10.所以直线MN 与平面PCD 所成角的正弦值为1010.【点睛】立体几何解答题的基本结构:(1)第一问一般是几何位置关系的证明,通常用判定定理;(2)第二问是计算,求角或求距离(求体积通常需要先求距离),通常可以建立空间直角坐标系,利用向量法计算.18.已知椭圆()2222:10x y C a b a b+=>>的左、右顶点分别为,A B ,且AB 4=,离心率为12,O 为坐标原点.(1)求椭圆C 的方程;(2)设P 是椭圆C 上不同于,A B 的一点,直线,PA PB 与直线4x =分别交于点,M N .证明:以线段MN 为直径作圆被x 轴截得的弦长为定值,并求出这个定值.(1)22143x y +=(2)证明见解析,定值为6【分析】(1)根据24AB a ==、离心率和椭圆,,a b c 之间关系可直接求得结果;(2)设(),P m n ,可得直线,PA PB 方程,进而确定,M N 两点坐标,设椭圆右焦点为F ,利用平面向量数量积的坐标运算可证得FM FN ⊥,可知以MN 为直径的圆过点()1,0F ,由此可确定线段MN 为直径作圆被x 轴截得的弦长.【小问1详解】由题意知:24AB a ==,解得:2a =,又离心率12c e a ==,1c ∴=,2223b a c ∴=-=,∴椭圆C 的方程为:22143x y +=.【小问2详解】由(1)得:()2,0A -,()2,0B ,设(),P m n ,则223412m n +=,即224123n m =-;直线():22n PA y x m =++,直线():22n PB y x m =--,M ∴点纵坐标62M n y m =+,N 点纵坐标22N n y m =-,即64,2n M m ⎛⎫ ⎪+⎝⎭,24,2n N m ⎛⎫ ⎪-⎝⎭,又椭圆右焦点为()1,0F ,63,2n FM m ⎛⎫∴= ⎪+⎝⎭ ,23,2n FN m ⎛⎫= ⎪-⎝⎭,()()22222231239412999990444m m n FM FN m m m --∴⋅=+=+=+=-=--- ,即FM FN ⊥,∴以MN 为直径的圆过点()1,0F ,又圆心横坐标为4,∴以MN 为直径的圆被x 轴截得的弦长为()2416⨯-=.即以线段MN 为直径作圆被x 轴截得的弦长为定值6.【点睛】关键点点睛:本题考查直线与椭圆综合应用中的定值问题的求解,本题求解定值问题的关键是能够利用平面向量数量积的坐标运算说明椭圆右焦点即为所求圆与x 轴的其中的一个交点,由圆的对称性可确定定值.19.已知抛物线2:4C y x =,O 为坐标原点,过焦点F 的直线l 与抛物线C 交于不同两点,A B .(1)记AFO V 和BFO V 的面积分别为12,S S ,若212S S =,求直线l 的方程;(2)判断在x 轴上是否存在点M ,使得四边形OAMB 为矩形,并说明理由.(1)440x -=;(2)不存在,理由见详解.【分析】(1)设直线l 方程为1x ty =+,()()1122,,,A x y B x y ,利用韦达定理及212y y =-计算可得答案;(2)假设存在点M ,使得四边形OAMB 为矩形,根据抛物线的性质推出OA OB ⊥不成立,则可得不存在点M ,使得四边形OAMB 为矩形.【小问1详解】设直线l 方程为1x ty =+,()()1122,,,A x y B x y 联立241y x x ty ⎧=⎨=+⎩,消去x 得2440y ty --=,得124y y t +=①,124y y =-②,又因为212S S =,则212y y =-③由①②③解得24t =±,即直线l 的方程为14x y =±+,即440x ±-=【小问2详解】假设存在点M ,使得四边形OAMB 为矩形,则,OM AB 互相平分所以线段AB 的中点在x 上,则AB x ⊥轴,此时()()1,2,1,2A B -41OA OB k k ∴=-≠-则OA OB ⊥不成立.故在x 轴上不存在点M ,使得四边形OAMB 为矩形。
2023届河北省石家庄市高中毕业年级教学质量检测(二)英语试卷学校:___________姓名:___________班级:___________考号:___________一、阅读理解The Nobel Prize has been awarded to women60times between1901and2022.These women have made outstanding contributions to the worlds of medicine,science,literature and so on.Here are four of them.Dorothy Crowfoot HodgkinAward:Nobel Prize in ChemistryYear:1964Dorothy Hodgkin was a British chemist whose interest in research began when,as a child,she received a chemistry book containing experiments with crystals.She studied at Oxford University and developed protein crystallography,which advanced the development of X-rays.This earned her the Nobel Prize.Gertrude B.ElionAward:Nobel Prize in Physiology or MedicineYear:1988Gertrude Elion won the Nobel Prize for her discoveries of important principles for drug treatment.Elion had watched her grandfather die of cancer,so she decided to fight the disease throughout her life.Elion,together with George Hitchings,with whom she shared the award, created a system for drug production that relies heavily on biochemistry.Toni MorrisonAward:Nobel Prize in LiteratureYear:1993Toni Morrison,whose book“Beloved”earned her the Pulitzer Prize and the American Book Award,was the first Black woman to ever receive the Nobel Prize in Literature.Born in Ohio,Morrison was a writer whose works are mostly about life in the Black community.She taught writing and served as an honorary professor at Princeton University.Esther DufloAward:Nobel Prize in EconomicsYear:2019“The elderly want stuffed animals not only for comfort,but they were conversation starters.It reminded them of their childhood,”she said.And she recalled one man said,“You know,I never wanted to go to school.And my father said if I would go that day,he would take me to the Brooklyn Zoo.And you know what?This was the first animal I saw there and it looked just like this giraffe.”Spreading joy isn’t just a holiday pastime for Patricia.She is also known as the“Happy Flower Lady”around Philadelphia,because she collects old flowers from stores and passes them out to anyone who needs a pick-me-up.“When you give,you really do get more back,”Patricia said.“Every morning,whether it’s the flowers or the stuffed animals,I have a purpose.”4.Why did Patricia go to the nursing homes in2009?A.To send gifts to the seniors.B.To read a story to the elderlyC.To get over her loneliness.D.To get rid of her kids’toys. 5.What does the underlined word“capping”in paragraph3mean?A.Limiting.B.Recording.C.Identifying.D.Doubling. 6.What can we infer from paragraph4?A.Seniors love good old days.B.Cute animals have healing effects on seniors.C.Giving makes seniors happy.D.Stuffed animals have more than one function.7.What does Patricia think of her giving experiences?A.Rewarding.B.Entertaining.C.Timely.D.Tough.A new study suggests classic paintings by well-known Impressionists Joseph Turner and Claude Monet may have been influenced by air pollution during the Industrial Revolution.The study,published in Proceedings of the National Academy of Sciences by authors from Harvard and Sorbonne universities,analyzed60oil paintings by Turner from1796to 1850and38paintings by Monet from1864to1901.Scientists don't know exactly how polluted the cities were during that time for lack of data.However,researchers say examining the works of Turner and Monet can give a picture of long-term environmental change with the air pollution.In particular,researchers said changes in local sulfur dioxide emissions from burningcoal may explain changes in the colour contrast and intensity of Turner,Monet,and others' works,even after taking into account the artistic trends and subject matter of the time.Scientists successfully measured painters'representation of nature,focusing on differences in local weather patterns which influenced colour in works painted in different parts of Europe.Paintings'done in Britain generally feature a paler blue sky than other works in other parts of the continent.Generally,artists can historically accurately represent their environment,so Turner and Monet were chosen because they are famous for their landscape and cityscape paintings and also because they were active during the Industrial Revolution, when air pollution grew at a rate never seen before.Additionally,researchers say that as the air in London and Paris became more polluted, the cities would appear hazier to the eyes as well as in photographs.By comparing the paintings of Turner and Monet to pictures from the era,they were able to determine the artists were at least partly influenced by the change in emissions.8.How did the researchers conduct the study?A.By referring to relevant historical records.B.By comparing the paintings of Turner and Monet.C.By relating the paintings to the air conditions then.D.By analyzing the data during the Industrial Revolution.9.What did the researchers find in the works of Turner and Monet?A.Air pollution at that time.B.Change in subject matter.C.Social trends of the period.D.Development of photography 10.What can we learn from paragraph5?A.European artists preferred landscape paintings.B.Scientists focused on studying weather patterns.C.Turner and Monet intended to present pollution.D.Britain suffered from air pollution most in Europe.11.What is the purpose of the text?A.To inform people of a new discovery.B.To instruct people to appreciatepaintings.C.To introduce the Industrial Revolution.D.To call on people to protect theenvironment.Many owners of electric cars have wished for a battery pack that could power their vehicle for more than a thousand miles on a single charge.Researchers have developed a lithium-air battery that could make that dream a reality.The new battery design could also one day power airplanes and trucks.The main new component in this lithium-air battery is a solid electrolyte(电解质)instead of the usual liquid variety.Batteries with solid electrolytes are not subject to safety problems with the liquid electrolytes used in lithium-ion and other battery types,which can overheat and catch fire. More importantly,the solid electrolyte can potentially boost the energy four times,which translates into longer driving range.For over a decade,scientists have been working overtime to develop a lithium(锂) battery that makes use of the oxygen in air.The lithium-air battery has the highest energy of any battery technology being considered for the next generation of batteries beyond lithium-ion.The new solid electrolyte is composed of a material made from relatively inexpensive elements,compared with the past designs.Besides,the chemical reaction in lithium-ion only involves one or two electrons stored per oxygen molecule(分子),while that for lithium-air battery involves four electrons.More electrons stored means higher energy.The new design is the first lithium-air battery that has achieved a four-electron reaction at room temperature.It also operates with oxygen supplied by air from the surrounding environment.The capability to run with air avoids the need for oxygen tanks to operate,a problem with earlier designs.“With further development,we expect our new design for the lithium-air battery to reach a record of1200watt-hours per kilogram,”said Curtiss,a researcher.“That is nearly four times better than lithium-ion batteries.”12.What contributes most to the lithium-ion battery?A.Lithium-ion.B.Oxygen molecules.C.Solid electrolytes.D.Liquidcomponent.13.What’s the problem with lithium-ion batteries?A.They burn easily if overheated.B.They are unsafe in production.C.They damage the environment.D.They require longer charging time. 14.How does the author organize paragraph4?A.By giving examples.B.By making comparisons.C.By presenting statistics D.By analyzing cause and effect. 15.What is the best title of the text?A.How Lithium-air Batteries Work B.What will Be Used to Power Airplanes C.Electric Cars Are Becoming More Popular D.New Batteries Offer LongerDriving Range二、七选五E.So actively being mindful of the present reduces stress.F.You'd better take a quick break to check in with your breathing.G.More minutes of movement add up to big health benefits over time.三、完形填空30.A.informed B.reminded C.warned D.convinced 31.A.turn B.quit C.wait D.rush 32.A.magic B.madness C.horror D.calmness 33.A.looked back B.turned around C.pulled over D.helped out 34.A.packed B.placed C.removed D.grabbed 35.A.kindness B.trust C.comfort D.admiration四、用单词的适当形式完成短文五、其他应用文46.假定你是李华,4月18日是国际古迹遗址日(World Heritage Day),你的外国笔友William发来邮件询问你校的活动计划。
安徽省八年级下学期期末考试数学试卷一、精心选一选,慧眼识金(每小题3分,共30分)1.(3分)下列各式是最简二次根式的是()A.B.C.D.考点:最简二次根式.专题:常规题型.分析:先根据二次根式的性质化简,再根据最简二次根式的定义判断即可.解答:解:A、=3,故不是最简二次根式,故A选项错误;B、是最简二次根式,符合题意,故B选项正确;C、=2,故不是最简二次根式,故C选项错误;D、=,故不是最简二次根式,故D选项错误;故选:B.点评:本题考查了对最简二次根式的定义的理解,能理解最简二次根式的定义是解此题的关键.2.(3分)下列各组数中,能构成直角三角形的是()A.4,5,6 B.1,1,C.6,8,11 D.5,12,23考点:勾股定理的逆定理.专题:计算题.分析:根据勾股定理逆定理:a2+b2=c2,将各个选项逐一代数计算即可得出答案.解答:解:A、∵42+52≠62,∴不能构成直角三角形,故A错误;B、∵12+12=,∴能构成直角三角形,故B正确;C、∵62+82≠112,∴不能构成直角三角形,故C错误;D、∵52+122≠232,∴不能构成直角三角形,故D错误.故选:B.点评:此题主要考查学生对勾股定理的逆定理的理解和掌握,要求学生熟练掌握这个逆定理.3.(3分)已知一次函数y=kx+b的图象如图所示,则k、b的符号是()A.k<0,b<0 B.k>0,b<0 C.k<0,b>0 D.k>0,b>0考点:一次函数图象与系数的关系.专题:数形结合.分析:由图可知,一次函数y=kx+b的图象经过二、三、四象限,根据一次函数图象在坐标平面内的位置与k、b的关系作答.解答:解:由一次函数y=kx+b的图象经过二、三、四象限,当k<0时,直线必经过二、四象限,故k<0,直线与y轴负半轴相交,故b<0.故选:A.点评:本题主要考查一次函数图象在坐标平面内的位置与k、b的关系.解答本题注意理解:直线y=kx+b所在的位置与k、b的符号有直接的关系.k>0时,直线必经过一、三象限;k<0时,直线必经过二、四象限;b>0时,直线与y轴正半轴相交;b=0时,直线过原点;b<0时,直线与y轴负半轴相交.4.(3分)(•潍坊)在某校“我的中国梦”演讲比赛中,有9名学生参加比赛,他们决赛的最终成绩各不相同,其中的一名学生要想知道自己能否进入前5名,不仅要了解自己的成绩,还要了解这9名学生成绩的()A.众数B.方差C.平均数D.中位数考点:统计量的选择.分析:9人成绩的中位数是第5名的成绩.参赛选手要想知道自己是否能进入前5名,只需要了解自己的成绩以及全部成绩的中位数,比较即可.解答:解:由于总共有9个人,且他们的分数互不相同,第5的成绩是中位数,要判断是否进入前5名,故应知道中位数的多少.故选:D.点评:此题主要考查统计的有关知识,主要包括平均数、中位数、众数、方差的意义.5.(3分)连接对角线互相垂直的四边形的四边中点,所构成的四边形一定是()A.矩形B.菱形C.正方形D.梯形考点:中点四边形.专题:探究型.分析:根据中位线的与对角线平行的性质,因此顺次连接四边中点可以得到一个相邻的边互相垂直的四边形,根据矩形的定义,邻边垂直的四边形为矩形.解答:已知:AC⊥BD,E、F、G、H分别为各边的中点,连接点E、F、G、H.求证:四边形EFGH是矩形.证明:∵E、F、G、H分别为各边的中点,∴EF∥AC,GH∥AC,EH∥BD,FG∥BD,(三角形的中位线平行于第三边)∴四边形EFGH是平行四边形,(两组对边分别平行的四边形是平行四边形)∵AC⊥BD,EF∥AC,EH∥BD,∴∠EMO=∠ENO=90°,∴四边形EMON是矩形(有三个角是直角的四边形是矩形),∴∠MEN=90°,∴四边形EFGH是矩形(有一个角是直角的平行四边形是矩形).故选:A.点评:本题考查的是矩形的判定方法,常用的方法有三种:①一个角是直角的平行四边形是矩形.②三个角是直角的四边形是矩形.③对角线相等的平行四边形是矩形.6.(3分)若的整数部分为x,小数部分为y,则的值是()A.B.C.1D.3考点:二次根式的加减法.专题:计算题.分析:因为的整数部分为1,小数部分为﹣1,所以x=1,y=﹣1,代入计算即可.解答:解:∵的整数部分为1,小数部分为﹣1,∴x=1,y=﹣1,∴=﹣(﹣1)=1.故选:C.点评:关键是会表示的整数部分和小数部分,再二次根式的加减运算,即将被开方数相同的二次根式进行合并.7.(3分)将直线y=﹣2x向右平移2个单位所得直线的解析式为()A.y=﹣2x+2 B.y=﹣2x﹣4 C.y=﹣2x﹣2 D.y=﹣2x+4考点:一次函数图象与几何变换.分析:根据“左加右减”的平移规律可由已知的解析式写出新的解析式.解答:解:将直线y=﹣2x向右平移2个单位所得直线的解析式为y=﹣2(x﹣2),即y=﹣2x+4.故选:D.点评:本题考查了一次函数图象与几何变换,掌握解析式“左加右减”的平移规律是解题的关键.8.(3分)某班50名学生身高测量结果如下表:身高 1.51 1.52 1.53 1.54 1.55 1.56 1.57 1.58 1.59 1.60 1.64人数 1 1 3 4 3 4 4 6 8 10 6该班学生身高的众数和中位数分别是()A.1.60,1.56 B.1.59,1.58 C.1.60,1.58 D.1.60,1.60考点:众数;中位数.专题:图表型.分析:找中位数要把数据按从小到大的顺序排列,位于最中间的一个数(或两个数的平均数)为中位数;众数是一组数据中出现次数最多的数据,注意众数可以不止一个.解答:解:表图为从小到大排列,数据1.60出现了10次,出现最多,故1.60为众数;1.58和1.58处在第25、26位,其平均数1.58,故1.58为中位数.所以本题这组数据的中位数是1.58,众数是1.60.故选:C.点评:本题属于基础题,考查了确定一组数据的中位数和众数的能力.注意找中位数的时候一定要先排好顺序,然后再根据奇数和偶数个来确定中位数,如果数据有奇数个,则正中间的数字即为所求.如果是偶数个则找中间两位数的平均数.9.(3分)(•南昌)某人驾车从A地上高速公路前往B地,中途在服务区休息了一段时间.出发时油箱中存油40升,到B地后发现油箱中还剩油4升,则从出发后到B地油箱中所剩油y(升)与时间t(小时)之间函数的大致图象是()A.B.C.D.考点:函数的图象.专题:图表型.分析:根据某人驾车从A地上高速公路前往B地,中途在服务区休息了一段时间,休息时油量不再发生变化,再次出发油量继续减小,即可得出符合要求的图象.解答:解:某人驾车从A地上高速公路前往B地,油量在减小;中途在服务区休息了一段时间,休息时油量不发生变化;再次出发油量继续减小;到B地后发现油箱中还剩油4升;只有C符合要求.故选:C.点评:本题考查了利用函数的图象解决实际问题,正确理解函数图象横纵坐标表示的意义,理解问题的过程,就能够通过图象得到函数问题的相应解决.10.(3分)(1998•内江)能判定四边形是平行四边形的条件是()A.一组对边平行,另一组对边相等B.一组对边相等,一组邻角相等C.一组对边平行,一组邻角相等D.一组对边平行,一组对角相等考点:平行四边形的判定.专题:证明题.分析:平行四边形的判定:①两组对边分别平行的四边形是平行四边形;②两组对边分别相等的四边形是平行四边形;③两组对角分别相等的四边形是平行四边形;④对角线互相平分的四边形是平行四边形;⑤一组对边平行且相等的四边形是平行四边形.根据判定定理进行推导即可.解答:解:如图所示,若已知一组对边平行,一组对角相等,易推导出另一组对边也平行,两组对边分别平行的四边形是平行四边形.故根据平行四边形的判定,只有D符合条件.故选:D.点评:此题主要考查学生对平行四边形的判定的掌握情况.在应用判定定理判定平行四边形时,应仔细观察题目所给的条件,仔细选择适合于题目的判定方法进行解答,避免混用判定方法.二、耐心填一填,一锤定音(每小题3分,共21分)11.(3分)(•襄阳)使代数式有意义的x的取值范围是x≥且x≠3.考点:二次根式有意义的条件;分式有意义的条件.专题:计算题.分析:根据被开方数大于等于0,分母不等于0列式进行计算即可得解.解答:解:根据题意得,2x﹣1≥0且3﹣x≠0,解得x≥且x≠3.故答案为:x≥且x≠3.点评:本题考查的知识点为:分式有意义,分母不为0;二次根式的被开方数是非负数.12.(3分)请你写出同时具备下列两个条件的一次函数的表达式(写出一个即可)y=﹣x ﹣6.(1)y随x的增大而减小;(2)图象经过点(2,﹣8)考点:一次函数的性质.专题:开放型.分析:由题可知,需求的一次函数只要满足k<0且经过点(2,﹣8)即可.解答:解:设函数关系式是y=kx+b(k≠0)由y随着x的增大而减小得k<0可设k=﹣1,将(2,﹣8)代入函数关系式,得b=﹣6因此一次函数表达式为y=﹣x﹣6.(此题答案不唯一)故答案为:y=﹣x﹣6.点评:本题考查了一次函数的性质.此类题要首先运用待定系数法确定k,b应满足的一个确定的关系式,再根据条件确定k的值,进一步确定b的值,即可写出函数关系式.13.(3分)已知,则x3y+xy3=10.考点:二次根式的化简求值.专题:计算题.分析:由已知得x+y=2,xy=1,把x3y+xy3分解因式再代入计算.解答:解:∵,∴x+y=2,xy=1,∴x3y+xy3=xy(x2+y2)=xy[(x+y)2﹣2xy]=(2)2﹣2=10.点评:解题时注意,灵活应用二次根式的乘除法法则,切忌把x、y直接代入求值.14.(3分)已知一组数据为:10;8,10,10,7,则这组数据的方差是 1.6.考点:方差.专题:计算题.分析:结合方差公式先求出这组数据的平均数,然后代入公式求出即可.解答:解:平均数为:(10+8+10+10+7)÷5=9,S2=[(10﹣9)2+(8﹣9)2+(10﹣9)2+(10﹣9)2+(7﹣9)2],=(1+1+1+1+4),=1.6,故答案为:1.6.点评:此题主要考查了方差的有关知识,正确的求出平均数,并正确代入方差公式是解决问题的关键.15.(3分)已知一次函数y=2x+1,则它的图象与坐标轴围成的三角形面积是.考点:一次函数图象上点的坐标特征.专题:数形结合.分析:求得函数与坐标轴的交点,然后根据三角形的面积公式即可求得三角形的面积.解答:解:一次函数的关系式是y=2x+1,当x=0时,y=1;当y=0时,x=﹣,它的图象与坐标轴围成的三角形面积是:×1×|﹣|=.故答案是:.点评:本题主要考查了一次函数图象上点的坐标特征.求线段的长的问题一般是转化为求点的坐标的问题解决.16.(3分)一个三角形的三边长分别为15cm、20cm、25cm,则这个三角形最长边上的高是12cm.考点:勾股定理的逆定理.专题:数形结合.分析:过C作CD⊥AB于D,根据勾股定理的逆定理可得该三角形为直角三角形,然后再利用三角形的面积公式即可求解.解答:解:如图:设AB=25是最长边,AC=15,BC=20,过C作CD⊥AB于D,∵AC2+BC2=152+202=625,AB2=252=625,∴AC2+BC2=AB2,∴∠C=90°,∵S△ACB=AC×BC=AB×CD,∴AC×BC=AB×CD15×20=25CD,∴CD=12(cm);故答案为:12.点评:本题考查勾股定理的逆定理和三角形的面积公式的应用.根据勾股定理的逆定理判断三角形为直角三角形是解答此题的突破点.17.(3分)如图,在直角坐标系中,正方形A1B1C1O、A2B2C2C1、A3B3C3C2、…A n B n C n C n 的顶点A1、A2、A3、…、A n均在直线y=kx+b上,顶点C1、C2、C3、…、C n在x轴上,﹣1若点B1的坐标为(1,1),点B2的坐标为(3,2),那么点B4的坐标为(15,8).考点:一次函数图象上点的坐标特征;正方形的性质.专题:规律型.分析:首先利用待定系数法求得直线A1A2的解析式,然后分别求得B1,B2,B3…的坐标,可以得到规律:B n(2n﹣1,2n﹣1),据此即可求解.解答:解:∵B1的坐标为(1,1),点B2的坐标为(3,2),∴正方形A1B1C1O边长为1,正方形A2B2C2C1边长为2,∴A1的坐标是(0,1),A2的坐标是:(1,2),代入y=kx+b得:,解得:,则直线A1A2的解析式是:y=x+1.∵A1B1=1,点B2的坐标为(3,2),∴点A3的坐标为(3,4),∴A3C2=A3B3=B3C3=4,∴点B3的坐标为(7,4),∴B1的纵坐标是:1=20,B1的横坐标是:1=21﹣1,∴B2的纵坐标是:2=21,B2的横坐标是:3=22﹣1,∴B3的纵坐标是:4=22,B3的横坐标是:7=23﹣1,∴B n的纵坐标是:2n﹣1,横坐标是:2n﹣1,则B n(2n﹣1,2n﹣1).∴B4的坐标是:(24﹣1,24﹣1),即(15,8).故答案为:(15,8).点评:此题主要考查了待定系数法求函数解析式和坐标的变化规律.此题难度较大,注意正确得到点的坐标的规律是解题的关键.三、用心做一做,马到成功(本大题共49分)18.(15分)计算(1)(﹣4)﹣(3﹣2);(2)(﹣)2+2×3;(3)5•(﹣4)(a≥0,b≥0).考点:二次根式的混合运算.专题:计算题.分析:(1)先把各二次根式化为最简二次根式,然后去括号后合并即可;(2)先利用完全平方公式和二次根式的乘法法则运算,然后合并即可;(3)利用二次根式的乘法法则运算.解答:解:(1)原式=4﹣﹣+=3;(2)原式=2﹣2+3+×3=5﹣2+2=5;(3)原式=﹣20=﹣20a2b.点评:本题考查了二次根式的混合运算:先把各二次根式化为最简二次根式,再进行二次根式的乘除运算,然后合并同类二次根式.19.(8分)如图,小红用一张长方形纸片ABCD进行折纸,已知该纸片宽AB为8cm,长BC为10cm.当小红折叠时,顶点D落在BC边上的点F处(折痕为AE).想一想,此时EC有多长?用你学过的方法进行解释.考点:翻折变换(折叠问题);勾股定理.专题:几何图形问题.分析:根据矩形的性质得AB=CD=8,BC=AD=10,∠B=∠C=90°,再根据折叠的性质得AF=AD=10,DE=EF,在Rt△ABF中,利用勾股定理计算出BF=6,则CF=BC﹣BF=4,设CE=x,则DE=EF=8﹣x,在Rt△CEF中利用勾股定理得到∴42+x2=(8﹣x)2,然后解方程即可.解答:解:∵四边形ABCD为矩形,∴AB=CD=8,BC=AD=10,∠B=∠C=90°,∵长方形纸片ABCD折纸,顶点D落在BC边上的点F处(折痕为AE),∴AF=AD=10,DE=EF,在Rt△ABF中,AB=8,AF=10,∴BF==6,∴CF=BC﹣BF=4,设CE=x,则DE=EF=8﹣x,在Rt△CEF中,∵CF2+CE2=EF2,∴42+x2=(8﹣x)2,解得x=3,即EC的长为3cm.点评:本题考查了折叠的性质:折叠是一种对称变换,它属于轴对称,折叠前后图形的形状和大小不变,位置变化,对应边和对应角相等.也考查了矩形的性质和勾股定理.20.已知:如图,在△ABC中,D是BC边上的一点,E是AD的中点,过点A作BC的平行线交于BE的延长线于点F,且AF=DC,连接CF.(1)求证:D是BC的中点;(2)如果AB=AC,试判断四边形ADCF的形状,并证明你的结论.考点:矩形的判定;全等三角形的判定与性质;等腰三角形的性质;平行四边形的性质.专题:证明题.分析:(1)可证△AFE≌△DBE,得出AF=BD,进而根据AF=DC,得出D是BC中点的结论;(证法2:可根据AF平行且相等于DC,得出四边形ADCF是平行四边形,从而证得DE是△BCF的中位线,由此得出D是BC中点)(2)若AB=AC,则△ABC是等腰三角形,根据等腰三角形三线合一的性质知AD⊥BC;而AF与DC平行且相等,故四边形ADCF是平行四边形,又AD⊥BC,则四边形ADCF是矩形.解答:(1)证明:∵E是AD的中点,∴AE=DE.∵AF∥BC,∴∠FAE=∠BDE,∠AFE=∠DBE.在△AFE和△DBE中,,∴△AFE≌△DBE(AAS).∴AF=BD.∵AF=DC,∴BD=DC.即:D是BC的中点.(2)解:四边形ADCF是矩形;证明:∵AF=DC,AF∥DC,∴四边形ADCF是平行四边形.∵AB=AC,BD=DC,∴AD⊥BC即∠ADC=90°.∴平行四边形ADCF是矩形.点评:此题主要考查了全等三角形的判定和性质,等腰三角形的性质,平行四边形、矩形的判定等知识综合运用.21.(9分)在一条直线上依次有A、B、C三个港口,甲、乙两船同时分别从A、B港口出发,沿直线匀速驶向C港.最终到达C港.设甲、乙两船行驶x(h)后,与B港的距离分别为y1、y2(km),y1、y2与x的函数关系如图.(1)填空:A、C两港口间的距离为120km,a=4;(2)请分别求出y1、y2与x的函数关系式,并求出交点P的坐标;(3)若两船的距离不超过10km时能够相互望见,求甲、乙两船经过多长时间正好相距10千米?考点:一次函数的应用.专题:综合题;分类讨论.分析:(1)从图中可以看出A、B两港是30km,B、C两港是90km,A、C两港口间的距离为30+90=120km,根据路程÷时间求出甲的速度,进而求出a的值;(2)利用待定系数法求出y1=,y2=15x(0≤x≤6),解方程组,即可求出点P的坐标.(3)先根据一次函数的图象求出乙的速度,再根据甲在乙船前和乙船后,及甲船已经到了而乙船正在行驶,三种情况进行解答即可.解答:解:(1)从图中可以看出A、B两港是30km,B、C两港是90km,所以A、C两港口间的距离为30+90=120(km);甲的速度为:30÷1=30(km/h),a=120÷30=4.故答案为:120,4;(2)当0≤x≤1时,由点(0,30),(1,0)求得y1=﹣30x+30;当1<x≤4时,由点(1,0),(4,90)求得y1=30x﹣30;即y1与x的函数关系式为y1=;由点(6,90)求得,y2=15x(0≤x≤6),即y2与x的函数关系式为y2=15x(0≤x≤6);由图象可知,交点P的横坐标x>1,此时y1=y2,解方程组,得,所以点P的坐标为(2,30);(3)由函数图象可知,乙船的速度为:90÷6=15(km/m).①甲在乙后10km,设行驶时间为xh,则x<2.如果0≤x≤1,那么(﹣30x+30)+15x=10,解得x=,不合题意舍去;如果1≤x<2,那么15x﹣(30x﹣30)=10,解得x=,符合题意;②甲超过乙后,甲在乙前10km,设行驶时间为xh,则x>2.由题意,得30x﹣30﹣15x=10,解得x=,符合题意;③甲船已经到了而乙船正在行驶,则4≤x<6.由题意,得90﹣15x=10,解得x=,符合题意;即甲、乙两船经过小时或小时或小时,正好相距10千米.点评:本题考查的是一次函数的图象及一次函数的应用,解答此题时要注意运用分类讨论的思想,不要漏解.22.(9分)如图,在线段AE的同侧作正方形ABCD和正方形BEFG(BE<AB),连接EG 并延长交DC于点M,作MN⊥AB,垂足为N,MN交BD于点P,设正方形ABCD的边长为1.(1)证明:四边形MPBG是平行四边形;(2)设BE=x,四边形MNBG的面积为y,求y关于x的函数关系式,并写出自变量x的取值范围;(3)如果按题设作出的四边形BGMP是菱形,求BE的长.考点:四边形综合题;平行线的判定.专题:几何综合题.分析:(1)分别证得DB∥ME和MN∥CB后利用两组对边分别相等的四边形是平行四边形即可证得结论;(2)根据正方形BEFG,从而可得CM=1﹣x,然后得y=(BG+MN)•BN即可.(3)由已知易得四边形BGMP是平行四边形,要使四边形BGMP是菱形则BG=MG,可得x=(1﹣x),解得x即可.解答:证明:(1)∵ABCD、BEFG是正方形∴∠CBA=∠FEB=90°,∠ABD=∠BEG=45°,∴DB∥ME(同位角相等,两直线平行).∵MN⊥AB,CB⊥AB,∴MN∥CB.∴四边形MPBG是平行四边形;(2)∵正方形BEFG,∴BG=BE=x.∵∠CMG=∠BEG=45°,∴CG=CM=BN=1﹣x.∴y=(GB+MN)•BN=(1+x)(1﹣x)=﹣x2(0<x<1);(3)∵四边形BGMP是菱形,∴BG=MG,∴x=(1﹣x),∴x=2﹣,∴BE=2﹣.点评:此题考查了四边形的综合知识,较复杂,但充分利用题目所给的条件,根据四边形性质列出方程即可解答.解答此题,不要局限于一种方法,可以多试几种方法,以提高解题的“含金量”.教师的职务是‘千教万教,教人求真’;学生的职务是‘千学万学,学做真人’。
钳工技能等级考试试卷(2级)一、选择题(每题1分,共35题)1.下列那项不是对中误差的来源()。
A.磁力表座安装不垂直;(正确答案)B.错误判断读数的正负号;C.联轴器制造和装配导致的表面偏差和同心度偏差;D.周围震动和强磁场引起的读数偏差。
2.立式设备,且吊耳位于设备顶部,吊装时吊装带之间的夹角最大不能超过()。
A.45°B.90°(正确答案)C.60°D.75°3.在用特种设备的日常维护保养、定期检查,至少每()进行一次。
A.1个月(正确答案)B.15天C.一个星期D.三个月4.特种设备作业人员考核两部分都是实行百分制,()为及格。
A.都是60分(正确答案)B.理论知识60分,实际操作应会;C.理论应知,实际操作应会5.手拉葫芦转动部分应定期进行润滑,但切勿将润滑油掺入()内,以防自锁失灵。
A.驱动链轮B.行星齿轮C.套筒D.摩擦片(正确答案)6.用涂色法检查变速机的中心距,当接触斑点在分度圆与齿顶圆之间,且成线状与齿顶平行时,中心距()。
A.正确B.太大(正确答案)C.太小D.歪斜7.鏨削时,鏨子前刀面与基面之间的夹角是()。
A、楔角B、前角(正确答案)C、后角8.千分尺的制造精度分O级和1级两种,二者相比,1级()。
A.最高B.稍高C.稍差(正确答案)D.很差9.利用分度头可在工件上划出圆的()。
A、等分线B、不等分线C、等分线或不等分线(正确答案)D、以上都不正确10.液压系统中的执行部分是指()。
A、液压泵B、液压缸(正确答案)C、各种控制阀D、输油管、油箱等11.装拆内角螺钉时,使用的工具是()A.套筒扳手B.内六方扳手(正确答案)C.锁紧扳12.水平仪在水平或垂直位置时,气泡处于玻璃管的位置()A.左边B.右边C.中央(正确答案)D.整个上部13.在使用误差比较小的水平仪测量设备的水平度时,应在被测量面上原地转()进行测量。
A、270°B、180°(正确答案)C、90°D、360°14.游标高度尺的作用()A测量零件的高度或精密划线;(正确答案)B测量台阶的深度C测量槽的深度D、以上都不是15.用铲车运输物品时,随行人员()。
2022-2023学年三年级(上)期中语文试卷1.联系语境,看拼音写词语。
ㅤㅤ9月1日,同学们穿着鲜艳的fúzhuāng 走进校园,ān jìng 的校园顿时热闹起来。
教室外面的qiáng bì上,老师们用yán 1iào 画上了美丽的图画,教室里的桌椅pái liè得整整齐齐,似乎也在欢迎同学们重返校园。
2.用“√”给加点字选择正确的读音(1)放假.(jiàjiǎ)了,爸爸带我去公园玩,我和几个小朋友在假.(jiàjiǎ)山里面捉迷藏,真有趣。
(2)马路上到处.(chùchǔ)都是交警叔叔,他们正在处.(chùchǔ)罚骑乘电动车没有佩戴头盔的人。
3.下面词语书写完全正确的一项是()A.手壁荒野摇头晃脑B.严历努力烈日炎炎C.票亮暖和五彩缤纷D.蜡烛胃口大吃一惊4.对下列加点字词理解错误的一项是()A.挑.促织(用肩担着)B.凌乱..(排列不整齐)C.明朗..(晴朗)D.白云生.处(产生,生出)5.按要求完成词句练习。
(1)秋天到了,林林和爸爸来到郊外,仰望蓝天白云,远眺树林、原野,爸爸不禁赞美道:“秋天,真美啊!”形容秋天的四字词语你还能再写几个吗?、、。
ㅤㅤ这时,林林看到一只五彩的蝴蝶兴奋地说:“爸爸,看,那只蝴蝶多美呀!”爸爸笑着说:“你能把蝴蝶的美说得再生动点吗?”林林想了想,说:“。
”嗯爸爸欣慰地点点头同样一句话换个说法就更加生动形象呢(把林林说的话补充完整,再在横线内填上合适的标点)(2)用修改符号在原句上修改语病。
①下课了,校园里顿时一下子热闹起来。
②看了这本书,流下了感动的泪水。
6.课内积累与运用。
(1)诗中有真情。
从“停车坐爱枫林晚,”中我们感受到了杜牧对秋天的喜爱之情;从“萧萧梧叶送寒声,”中我们感受到了诗人客居他乡的孤寂以及深深的思乡之情;从“一年好景君须记,橘”中我们感受到了苏轼对刘景文的鼓励之情,如果诗人是在冬天写诗来勉励刘景文,他可能会写:“一年好景君须记,”。
《汽车电工电子技术》试题(2)
一、选择题:(每空2分,共30分)
1、下列设备中,其中()通常作为电源。
A、发电机
B、电视机
C、电炉
2、两个电阻值均为100Ω的电阻并联后其总阻值为()。
A、50
B、100
C、200
3、下列设备中属于电路组成中中间环节的是( )
A、连接导线
B、电源
C、白炽灯
4、电动势的方向规定为( )。
A、由正极指向负极
B、由负极指向正极
C、不定
5、两相触电时,人体承受的电压是()。
A、线电压
B、相电压
C、跨步电压
6、周期T和频率f三者之间的关系正确的为()
A、T=1/f
B、Tf
C、T与f无关
7、汽车上常用的发电机是()。
A、单相交流发电机
B、三相同步交流发电机
C、直流发电机
8、汽车上常用的电动机是()。
A、单相交流电动机
B、直流串励式电动机
C、三相交流电动机
9、已知某正弦量i=52sin(314t+30°)A,则其最大值为()A。
A、5
B、52
C、10
10、我国用电安全规程中把()定为安全电压。
A、50V
B、100V
C、36V
11、我国工业用电频率是()HZ。
A、40
B、50
C、60
12、融断器在电路中主要起()保护。
A、短路
B、过载
C、欠压
13、安全保护措施有保护接地,漏电保护器和()。
A、保护接零
B、减少电流
C、减少电压
14、当在三相四线线制供电线路中,线电压VL和相电压UP的数量关系是()。
A、UL=2UP
B、UP=UL
C、UL=3UP
15、万用表测量电阻时,必须()。
A、带电测量
B、放在电路中测量
C、断电测量
二、判断并改错:(每空2分,共24分)
1、电容元件是耗能元件。
()
2、通过电阻的并联可以达到分流的目的,电阻越大,分流作用越显著。
()
3、大小和方向都随时间变化的电流称为交流电流。
()
4、万用表使用结束后应置于交流电压的最高档或OFF档。
()
5、只要触电电压不高,触电时流经人体的电流再大也不会有危险。
()
6、蓄电池在电路中必定是电源,总是把化学能转换为电能。
()
7、通常规定,自由电子运动的方向为电流的方向。
()
8、变压器主要由铁心和绕组两部分组成,铁心构成磁路部分,绕组构成电路部分。
(√)
9、测量时,电流表应串入被测电路中,电压表应并入电路中。
()
10、发电机的功能是将非电能转化为电能,电动机的功能是将电能转化为机械能。
(√)
11、汽车电动机在空载或轻载运行时速度很高,容易发生飞车事故。
()
12、汽车点火线圈是利用互感原理制成的。
()
三、简答题(20分)
1、简述用万用表测量电阻的方法。
(8分)
2、电位与电压有什么区别。
(6分)
3、
3、汽车用直流串励式电动机的工作特性有哪些?(6分)
四、作图题(6分)
1、请你分别作出电阻、电容、电感线圈、变压器、电流表符号。
五、计算题(20分)
1、一个额定值为220V、1000W的电阻炉,接在220V的交流电源上,求:通过电阻炉的电流和它的电阻。
如烧2小时,所消耗的电能为多少?(7分)
2、接在220V交流电源上的单相变压器,其二次绕组电压为110V,若二次绕组的匝数为350匝,求一次绕组匝数为多少?(6分)
3、如图所示,电源电动势E=24V,内电阻R0=0.5Ω,外电阻R=11.5Ω,求电路中电流I 及电阻R两端的电压U。
(7分)
《汽车电工电子技术》试题(2)答案
一、选择题:
AAABA ABBBC BAACC
二、判断并改错:
1×储能元件2×电阻越小,分流作用越明显3×作周期性变化 4 √5×有危险6×充电时是负载7×正电荷8√9√10√11√12√
三、简答题:
1、一是选择合适量程并欧姆调零;二是用两表笔分别接触被测电阻两端,从右往左正确读数;三尽量使指针指向中间位置;四是测量结束后,拔出表笔,将选择开关置于OFF档或交流电压最大档。
2、电位是相对量,随参考点的改变而改变,电压是绝对量,与参考点的改变无关。
3、一是起动转矩大且过载能力强;二是重载转速低,轻载转速高。
四、略
五、
1、I=P/U=1000/220=4.55A R=U/I=220/4.55=48.4Ω
W=Pt=1kw×2h=2度
2、220/110=N/350 N=700匝
3、I=2A U=23V。