限时训练(30)答案
2021年内蒙古中考英语重点题型限时训练：完形填空+ 阅读理解(C)+ 选词填空+ 任务型阅读
完形填空+ 阅读理解(C)+ 选词填空+ 任务型阅读[限时:30分钟]Ⅰ.完形填空A teacher decided to have her class play a game. The teacher told each student to bring a plastic bag with a few potatoes in it to school. Each student would “name” their potatoes after people they did not like. 1, the number of potatoes would be 2depending on how many people each student hated.The next day, with their potatoes, all the students went to school 3the game. Some kids had just one or two potatoes, while others had as many as five or six. The teacher then told the children that they would have to carry their potatoes with 4wherever they went for one week. Several days 5, some of the students started to complain(抱怨), as their potatoes began to rot(腐烂) and 6bad. The students who carried 7potatoes began to get unsatisfied with the heavy bags.One week later, the game 8. The teacher asked, “How did you 9carrying around your potatoes for a week?”The students complained once again. The teacher simply smiled and said, “This is what it’s like to carry hatred(仇恨) in your heart. You have to carry it with you wherever you go. If you can’t tolerate(容忍) carrying rotten potatoes for one week, how can you imagine having 10in your heart for a whole lifetime? Forgive others and move on with your life.”()1.A.However B.In a wordC.ThereforeD.After all()2.A.different B.similarC.the sameD.small()3.A.to watch B.to join inC.to winD.to lose()4.A.it B.thatC.themD.school bags()5.A.walked B.passed onC.passedD.walked by()6.A.taste B.smellC.soundD.feel()7.A.few B.someC.moreD.any()8.A.continued B.was doneC.beganD.was over()9.A.feel like B.look likeC.enjoyD.just like()10.A.love B.happinessC.friendshipD.hateⅠ. 阅读理解How can cactus(仙人掌) help the world? It can provide a new kind of sustainable fuel(可持续燃料). Nopalimex, a company in Mexico, has made one of the world’s first cactus-powered factories. The idea came to Sosa in Nopalimex when he was looking for ways to save money for his food factory. He now powers his factory with cactus gas(气体). The cost to produce the gas is half the cost of electricity.Soon, the gas produced by Nopalimex will also be used in cars. Nopalimex’s gas is made by using the prickly pear(刺梨)—a kind of cactus. To make the gas, the prickly pear is mixed together with manure(肥料). Then the mixture produces the gas that can be used as fuel.Why cactus? Fuel can be made from other plants such as corn, but there are a few reasons why cactus is a betterchoice. First, prickly pears need very little water and very little care, and grow well in hot temperatures. Today, these characteristics are key. Also, unlike corn, prickly pears don’t need space that could be used for other food plants. They can grow in areas where many food plants can’t grow. Last, after making gas from prickly pears and manure, their byproducts(副产品) can be used to help grow food.Scientists still need to do more research on making and using prickly pear gas. As projects like Nopalimex show, we have the possibility to produce more sustainable fuel to power our lives.1.How can cactus help the world?()A.By saving farmers’ money.B.By providing a new kind of sustainable fuel.C.By taking the place of corn.D.By producing a lot of electricity and gas.2.Why does Sosa power his factory with cactus gas?()A.Because he wants to save money for his food factory.B.Because he has grown a lot of cactus and corn in his town.C.Because he wants to be well-known around the world.D.Because he wants to grow cactus instead of corn.3.What does the underlined word “mixture” in Paragraph 2 refer to?()A.The Nopalimex company.B.The manure.C.The prickly pear and manure.D.Cactus.4.What is Paragraph 3 mainly about?()A.How cactus is used to produce gas.B.Where we can grow a lot of cactus.C.What Nopalimex does with cactus.D.Why cactus is a better choice to make fuel.Ⅰ. 选词填空阅读下列短文,用方框内所给单词的正确形式填空。
北师大版高一英语必修3_Unit9_30分钟限时训练题
Unit9 30分钟限时训练题Ⅰ.单项填空1．________ group wins on Saturday will go through to the world competition. A．No matter what B．No matter whichC．Whatever D．Whichever2．Children under six are not ________ to school except those of extraordinary intelligence.A．permitted B．accepted C．admitted D．received 3．Nowadays, too many children ________TV. That's bad for their eyesight and TV also keeps them from communicating with others.A．addicts to watchingB．are addicted to watchC．addict themselves to watchD．are addicted to watching4．My house is very ________ for getting to work as it is only a few minutes' walk from the station.A．comfortable B．suitable C．convenient D．available5．________ those who were not listening the first time, I will repeat the question. A．To the benefit of B．With the benefit ofC．For the benefit of D．With the benefit to6．The doctor had almost lost hope at one point, but the patient finally ________. A．pulled through B．pulled outC．pulled up D．pulled over7．—Do you think that housing price will keep ________ in the future?—Sorry, I have no idea.A．lifting up B．going upC．bringing up D．growing up8．________ your rotten idea, we went the long way.A．Thanks to B．Because C．Due to D．Since9．An earthquake struck this area，________ a lot of damage.A．making B．causing C．done D．caused10．The teacher proposed that Jack _____ maths or physics instead of English because he was quick at numbers.A．must study B．could studyC．studied D．studyⅡ.完形填空There are many different ways of seeing a town for the first time. One of them is to walk around it, a guidebook__11__hand. Of course, we may __12__ with our guidebooks the history and __13__ developments of a town and get to know them. __14__ then, if we take our time and __15__ in a town for a while, we may get to know it better. When we __16__it as a whole, we begin to have some __17__ ，which even the best guidebooks do not answer. Why is the town just __18__ this, this shape, this plan, this size? Why do its streets __19__in this particular way, and not in any __20__way?Here even the best guidebook__21__ us. One can't find in it the information about how a town has developed to the__22__ appearance. It may not describe the original (最初的) __23__ of a town. However, one may get some idea of what it__24__ look like by walking around the town. One can also imagine _25__the town was first planned and built. Then one can learn more about in what direction the town __26__ to develop.What is the __27__ of studying towns in this way? For me, it is __28__ that one gets a greater depth of pleasure by visiting and seeing a town with one's own eyes. A __29__ visit to a town may help one better understand why it is attractive __30__ just reading about it in a guidebook.11．A. in B．at C．by D．on12．A. write B．study C．tell D．remember13．A. strange B．similar C．separate D．special14．A. But B．Before C．Since D．Until15．A. march B．work C．stay D．wait16．A. look at B．look after C．look for D．look up17．A. ideas B．opinions C．feeling D．questions18．A. of B．for C．like D．as19．A. open B．run C．begin D．move20．A. one B．more C．other D．such21．A. helps B．tricks C．fails D．satisfies22．A. old B．normal C．first D．present23．A. capital B．meaning C．design D．change24．A. used to B．seemed to C．had to D．happened to25．A. what B．how C．when D．where26．A. stops B．appears C．starts D．continues27．A. point B．view C．problem D．difficulty28．A. nearly B．simply C．generally D．hardly29．A. costly B．formal C．group D．personal30．A. from B．than C．through D．withⅢ.阅读理解AIn 1885, a young doctor named Arthur Conan Doyle opened offices in London.He wanted to be a successful doctor, but for some reasons he never found enough patients. To pass the time, he began to write stories and send them to the newspapers.Conan Doyle's stories were about a clever detective, Sherlock Holmes. Conan Doyle wrote that Sherlock Holmes lived in Baker Street in London, and people with problems came to Sherlock Holmes with their problems, too. He was able to solve mysteries (疑难案件) that the cleverest policemen in England were unable to figure out.Sometimes Sherlock Holmes could solve a mystery without leaving his chair. He listened carefully to the information his client gave and figured out the answer. At other times he spent days or weeks looking for clues. Sherlock Holmes travelled to different cities and countries to solve the mysteries. Sometimes he wore disguises, pretending to be an old man, or a sailor. Holmes did anything to find out the answer to the mysteries he was working on.Sherlock Holmes is the most famous detective in English literature，but many people don't understand that he is a fictional character, not a real person. The English post offices report that people still send mail to Sherlock Holmes in Baker Street. Even he gets more than 2，000 letters every year.31．Conan Doyle began to write stories perhaps because ________．A．he wanted to tell something about his patientsB．he wasn't good at medicineC．he wanted to make less moneyD．most people were strong at that time32．Conan Doyle got to write very good detective stories because ________．A．many people asked him to solve their mysteriesB．he got a lot of experience in solving mysteriesC．he was a person with great literary quality and talentD．he was able to help those who came to see him with their problems 33．Sherlock Holmes________．A．was only an ordinary detectiveB．never existed in the worldC．was one of the members of the police in LondonD．was a real detective who was named by Conan Doyle34．The phrase “wore disguises” in the fourth paragraph means “ ________”．A．introduced oneselfB．was in old clothesC．changed one's clothes or one's appearanceD．seemed to be poor and helpless35．Instead of being a famous doctor，Arthur Conan Doyle came to be successful in writing because ________.A．many people wrote letters to him asking about the storiesB．the character he wrote about was thought to be a real personC．he was finally employed by a police stationD．he earned a lot of money by writing such a storyBA new study suggests that the round-the-clock(24小时的)availability that cell phones have brought to people's lives may be taking a toll on family life. The study，which followed more than 1，300 adults over 2 years, found that those whoconsistently used a mobile phone throughout the study period were more likely to r eport negative “spillover” between work and home life—and，in turn，less satisfaction with their family life.Spillover essentially(本质上)means that the line between work and home begins to become unclear. Work life may invade home life when a parent is taking job-related calls at home，for instance—or family issues may start to take up work time. For example，a child may call mum at work，telling her “microwave exploded”，explained Noelle Chesley，an assistant professor of sociology at the University of Wisconsin-Milwaukee and the author of the study. The problem with cell phones seems to be that they are allowing for even more spillover between work and home.This may be especially true for working women，the study found. Among men，consistent use of mobile phones seemed to allow more work issues to creep (潜入)into family time. But for women，the spillover tended to go in both directions. Being “connected” meant that work cut into home time，and family issues came into work life.Cell phones seem to be opening more lines for stressful exchanges among family members. But there may be ways to control the spillover，according to Chesley. Employers, she said，could look at their policies on contacting employees after hours to make sure their expectations are “reasonable”．For their part，employees could decide that cell phones go off during family time, Chesley said.36．What does the underlined phrase “taking a toll on” probably mean in Paragraph 1? A．Explaining. B．Founding. C．Damaging. D．Extending. 37．According to Chesley，what is the best solution to the problem caused by cell phones?A．Refuse to use cell phones.B．Separate work hours from family time.C．Ignore coming calls during family time.D．Encourage women to stay at home.38．We can learn from the passage that ________．A．cell phones make the line between work and home unclearB．cell phones seem to be convenient to familiesC．cell phones affect men as much as womenD．we can do nothing to solve the problem39．What is the main idea of the passage?A．How to control the negative spillover caused by cell phones.B．Cell phones cause negative “spillover” between work life and home life. C．Consistent use of cell phones makes people feel less satisfied with their work. D．How work life invades home life.参考答案及解析Ⅰ.1.D考查主语从句的引导词。
九年级英语限时训练(附参考答案)
九年级英语限时训练（附参考答案）（满分40分，时间30分钟）一.单词拼写（共5小题，每题2分，满分10分）根据句意和首字母或汉语提示，将单词的正确形式完整地写在横线上。
1. —Cindy, what kind of restaurants do you like ?—I p_____ restaurants that can provide customers with free Wi - Fi.2. Mr.King is very P ______. He often explains difficult problems many times until we understand.3. It’s_________（危险的）for people to use the mobile phone while crossing the street.4. China has been making many great _____（成就）in every field these years, which amazes the world.5. Teenagers should be_________（鼓励）to learn and spread Chinese traditional culture.二、综合填空（共10小题，每题2分，满分20分）根据短文内容，用方框中所给词语的适当形式填空，使文章通顺、完整。
（每词限用一次）hour, power, a, matter, pain, compete, good, point, keep, createEileen Gu was born in San Francisco, California to an American father and a Chinese mother. While 6._______ for the United States in her earlier years, Gu announced her decision to ski for China in 2019 after her first World Cup Italy. In the interview, Gu mentioned her 8.5 7.______training a day, which gives her the confidence to win.She scored 1,580 8. ________out of a maximum 1,600 in the SAT, the test used for college admissions in the United States. “I encourage you all to step out of your comfort zone to show the boys that girls are just as 9._________ as they are.” Gu said. “I’m not trying 10._________ anyone happy. I’m 11.________18-year-old girl living my best life. It doesn’t really12. _____ if other people are happy or not, because I feel I am doing my 13._______. I’m enjoying the entire process and I’m using my voice 14._______ as much positive change as I can, fo r the voice that will listen to me.”She’s not afraid of hardship, tiredness, and 15.______ .she’s especially positive and optimistic. she’s quite burning. A ball of flame was surrounding her.三、阅读理解（共5个小题，每题2分，满分10分）阅读下面的短文，从每题所给的A、B、C、D四个选项中，选出最佳答案。
2020新课标高考语文二轮总复习专题限时训练：2-8 名篇名句默写 Word版含解析
[课时训练]限时练(三十)1．补写出下列句子中的空缺部分。
(1)王湾《次北固山下》中，“______________，______________”两句写拂晓行船的情景，作者无意说理，却在描写景物、节令之中，蕴含着一种自然的理趣。
(2)杜牧《阿房宫赋》中“________________，________________，______________”连用整齐的短句，写秦朝统治者大肆挥霍从六国搜刮来的珍宝，极不珍惜。
【答案】(1)海日生残夜江春入旧年(2)鼎铛玉石金块珠砾弃掷逦迤2．补写出下列句子中的空缺部分。
(1)苏轼《赤壁赋》中，“__________________，__________________”两句生动形象地描绘出月亮在夜空中缓慢移动的状态，逼真传神。
(2)辛弃疾《永遇乐·京口北固亭怀古》中，写古代英雄叱咤风云、驰骋疆场的名句是“______________，________________”。
(3)《荀子·劝学》中，“_____________，_____________”两句强调了整天空想不如片刻学习收获大的道理。
【答案】(1)月出于东山之上徘徊于斗牛之间(2)金戈铁马气吞万里如虎(3)吾尝终日而思矣不如须臾之所学也3．补写出下列句子中的空缺部分。
(1)周敦颐在《爱莲说》中用“________________”和“________________”分别表达对菊花和牡丹的看法。
(2)李白在《蜀道难》中，用禽、兽都不能越过蜀道中的高山来侧面烘托蜀道之难的两句诗是“__________________，__________________”。
(3)在《赤壁赋》中，苏轼感觉自己“浩浩乎”“飘飘乎”的具体原因是作者与客在“水光接天”的环境下“________________，________________”。
【答案】(1)花之隐逸者也花之富贵者也(2)黄鹤之飞尚不得过猿猱欲度愁攀援(3)纵一苇之所如凌万顷之茫然4．补写出下列句子中的空缺部分。
2020中考英语30分钟限时训练 完形填空+还原短文+回答问题+词语运用 含答案
完形+还原短文+阅读填表格+词语运用(限时:30分钟)Ⅰ.[2019·乐山改编]完形填空A group of boys gathered around a tree. “What a tall tree!” they said to each other. “It would be 1 to climb to the top!”The group of boys then decided to play a game to see who could climb to the top of the tree 2 . Their mothers were sitting not far away, looking on at their children as they 3 . One of the climbers was an 8-year-old boy named David. He was the shortest child in the group. Nobody thought he would win the competition.Then the game started. All of the boys tried their best to climb as 4 as they could. Although they all made it halfway up the tree before David did, he reached the top of the tree fastest 5 . His mother was proud to see this. She asked him, “David, how did you 6 to reach the top of the tree so quickly?”“It was easy,” David said. “The other children kept looking down as they climbed. When they realized how high they were, they got scared(恐惧的) and were afraid of 7 down. I, however, looked only 8 . When I saw how close I was, I kept going higher and higher until I reached the top.”It is true in life that if we just keep going forward without looking back, we are more likely to reach our goals(目标).( )eful B.possible C.exciting( )st B.finally C.first( )3.A.studied B.played C.jumped( )4.A.high B.safely C.carefully( )5.A.as well B.in the end C.in time( )6.A.manage B.hope C.imagine( )7.A.looking B.climbing C.falling( )8.A.down B.up C.outⅡ.还原短文请阅读下面短文,根据短文内容,从方框内所给的选项中选出能填入空白处的最佳选项,使短文意思通顺。
高中数学必修4课后限时训练30 三角函数的积化和差、和差化积
高中数学必修4课后限时训练30 三角函数的积化和差、和差化积题组1：基础巩固一、选择题1．sin75°－sin15°的值为( )A ．12B ．22C ．32D ．－12 答案：B 解析：sin75°－sin 15＝2cos 75°＋15°2sin 75°－15°2＝2×22×12＝22.故选B. 2．已知cos(α＋β)cos(α－β)＝13，则cos 2α－sin 2β的值为( ) A ．－23 B ．－13C ．13D ．23答案：C解析：由已知得cos 2αcos 2β－sin 2αsin 2β＝13， ∴cos 2α(1－sin 2β)－sin 2αsin 2β＝13， 即cos 2α－sin 2β＝13. 3．化简cos α－cos3αsin3α－sin α的结果为( ) A ．tan α B ．tan2αC ．cot αD ．cot2α答案：B解析：原式＝－2sin2αsin (－α)2cos2αsin α＝2sin2αsin α2cos2αsin α＝tan2α.4．已知cos 2α－cos 2β＝m ，那么sin(α＋β)sin(α－β)等于( )A ．－mB ．mC ．－m 2D ．m 2答案：A解析：sin(α＋β)sin(α－β)＝(sin αcos β＋cos αsin β)(sin αcos β－cos αsin β)＝sin 2αcos 2β－cos 2αsin 2β＝(1－cos 2α)cos 2β－cos 2α(1－cos 2β)＝cos 2β－cos 2αcos 2β－cos 2α＋cos 2αcos 2β＝cos 2β－cos 2α＝－m .5．计算sin105°cos75°的值是( ) A ．12 B ．14C ．－14D ．－12 答案：B解析：sin105°cos75°＝12(sin180°＋sin30°)＝14.6．sin10°＋sin50°sin35°·sin55°＝( ) A ．14B ．12C ．2D ．4答案：B 解析：sin10°＋sin50°sin35°sin55°＝2sin30°cos20°－12(cos90°－cos20°) ＝14cos20°12cos20°＝12. 二、填空题7．在△ABC 中，已知sin B sin C ＝cos 2A 2，则此三角形是________三角形． 答案：等腰解析：sin B sin C ＝cos 2A 2＝1＋cos A 2， ∴2sin B sin C ＝1－cos(B ＋C )＝1－cos B cos C ＋sin B sin C ，∴cos B cos C ＋sin B sin C ＝1，即cos(B －C )＝1又－π<A <B <π，∴A －B ＝0，∴A ＝B .故△ABC 是等腰三角形．8．cos40°＋cos60°＋cos80°＋cos160°＝________.答案：12解析：原式＝cos40°＋cos80°＋cos60°－cos20°＝2cos60°·cos(－20°)＋cos60°－cos20°＝cos60°＝12. 三、解答题9．求证：sin(α＋β)cos α－12[sin(2α＋β)－sin β]＝sin β. 解析：解法一：左边＝sin(α＋β)cos α－12[sin 〔(α＋β)＋α〕－sin β] ＝sin(α＋β)cos α－12[sin(α＋β)cos α＋cos(α＋β)sin α]＋12sin β＝12[sin(α＋β)cos α－cos(α＋β)sin α]＋12sin β ＝12sin[(α＋β)－α]＋12sin β＝sin β＝右边． 解法二：左边＝sin(α＋β)cos α－12⎝ ⎛⎭⎪⎫2cos 2α＋β＋β2sin 2α＋β－β2 ＝sin(α＋β)cos α－cos(α＋β)sin α＝sin[(α＋β)－α]＝sin β＝右边．题组2：能力提升一、选择题1．已知sin(α－β)·cos α－cos(α－β)·sin α＝m ，且β为第三象限角，则cos β等于( )A ．1－m 2B ．－1－m 2C ．1＋m 2D ．－m 2－1答案：B解析：sin(α－β)cos α－cos(α－β)sin α＝sin(－β)＝－sin β，∴sin β＝－m .又β为第三象限角，∴cos β＝－1－m 2.2．若sin α＋sin β＝33(cos β－cos α)且α∈(0，π)，β∈(0，π)，则α－β等于( ) A ．－2π3 B ．－π3C ．π3D ．2π3 答案：D解析：∵α、β∈(0，π)，∴sin α＋sin β>0.∴cos β－cos α>0，∴cos β>cos α，又在(0，π)上，y ＝cos x 是减函数．∴β<α∴0<α－β<π，由原式可知：2sin α＋β2·cos α－β2＝33⎝ ⎛⎭⎪⎫－2sin α＋β2·sin β－α2， ∴tan α－β2＝3∴α－β2＝π3∴α－β＝2π3. 3．在△ABC 中，若B ＝30°，则cos A sin C 的取值范围是( )A ．[－1,1]B ．[－12，12] C ．[－14，34] D ．[－34，14] 答案：C解析：cos A sin C ＝12[sin(A ＋C )－sin(A －C )]＝14－12sin(A －C )，∵－1≤sin(A －C )≤1， ∴cos A sin C ∈⎣⎡⎦⎤－14，34. 4．tan70°cos10°(3tan20°－1)等于( )A ．1B ．－1C ．12D ．－12答案：B解析：原式＝cot20°cos10°(3tan20°－1) ＝cot20°cos10°3sin20°－cos20°cos20°＝cot20°cos10°2sin (20°－30°)cos20°＝－2sin10°cos10°cot20°cos20°＝－1. 二、填空题 5．sin 220°＋cos 280°＋3sin20°·cos80°＝________.答案：14 解析：原式＝1－cos40°2＋1＋cos160°2＋32sin100°－32sin60° ＝14－12cos40°－12cos20°＋32sin100° ＝14－12×2cos30°cos10°＋32cos10° ＝14－32cos10°＋32cos10°＝14.6．计算1tan10°－4cos10°＝________. 答案：3解析：1tan10°－4cos10°＝cos10°－2sin20°sin10°＝cos10°＋2sin (30°－10°)sin10°＝2cos30°sin10°sin10＝ 3. 三、解答题7．求函数y ＝sin 4x ＋23sin x cos x －cos 4x 的最小正周期和最小值；并写出该函数在[0，π]上的递增区间． 解析：y ＝sin 4x ＋23sin x cos x －cos 4x＝(sin 2x ＋cos 2x )(sin 2x －cos 2x )＋3sin2x＝3sin2x －cos2x ＝2sin ⎝⎛⎭⎫2x －π6. 故该函数的最小正周期是π；最小值是－2.递增区间为⎣⎡⎦⎤0，π3，⎣⎡⎦⎤56π，π. 8．在△ABC 中，求证：(1)sin 2A ＋sin 2B －sin 2C ＝2sin A sin B cos C ；(2)sin A ＋sin B －sin C ＝4sin A 2sin B 2cos C 2. 解析：(1)左边＝sin 2A ＋1－cos2B 2－1－cos2C 2＝sin 2A ＋12(cos2C －cos2B ) ＝sin 2(B ＋C )＋sin(B ＋C )sin(B －C )＝sin(B ＋C )[sin(B ＋C )＋sin(B －C )]＝sin(B ＋C )2sin B cos C ＝2sin A sin B cos C ＝右边， ∴等式成立．(2)左边＝sin(B ＋C )＋2sin B －C 2cos B ＋C 2＝2sin B ＋C 2cos B ＋C 2＋2sin B －C 2cos B ＋C 2＝2cos B ＋C 2⎝ ⎛⎭⎪⎫sin B ＋C 2＋sin B －C 2 ＝4sin A 2sin B 2cos C 2＝右边，∴原等式成立． 9．讨论函数f (x )＝12cos(2x －2α)＋cos 2α－2cos(x －α)·cos x ·cos α的周期、最值、奇偶性及单调区间． 解析：f (x )＝12cos(2x －2α)＋1＋cos2α2－2cos(x －α)cos x ·cos α ＝12＋12[cos(2x －2α)＋cos2α]－[2cos(x －α)·cos α]cos x ＝12＋cos x ·cos(x －2α)－cos x [cos x ＋cos(x －2α)] ＝12－cos 2x ＝12－1＋cos2x 2＝－12cos2x . ∴函数的最小正周期T ＝2π2＝π. f (x )max ＝12，此时cos2x ＝－1，即2x ＝2k π＋π，k ∈Z ，x ＝k π＋π2，k ∈Z ； f (x )min ＝－12，此时cos2x ＝1， 即2x ＝2k π，k ∈Z ，x ＝k π，k ∈Z .f (－x )＝f (x )，∴f (x )为偶函数．由2k π≤2x ≤2k π＋π，k ∈Z ，即k π≤x ≤k π＋π2，k ∈Z . ∴函数f (x )的增区间为[k π，k π＋π2](k ∈Z )． 由2k π＋π≤2x ≤2k π＋2π，k ∈Z ，即k π＋π2≤x ≤k π＋π，k ∈Z . ∴函数f (x )的单调减区间为[k π＋π2，k π＋π]，k ∈Z .。
2020中考英语30分钟限时训练 完形+还原短文+阅读填表格+词语运用 附答案
完形+还原短文+阅读填表格+词语运用(限时:30分钟)Ⅰ.[2019·呼和浩特改编]完形填空“The grass looks greener on the other side of the fence.” That's an old 1 in English. It means other places often look better, more interesting than the place in 2 you live. Some people worry 3 young Chinese are beginning to feel that way. They see young Chinese paying no attention to Chinese culture and, 4 , buying Japanese cartoon books, watching Korean soap operas and even celebrating Western holidays.Foreign books and soap operas are good, 5 Chinese writers and actors are just as good. As for holidays, Christmas is nice, but it can 6 have the meaning for Chinese that the Spring Festival has, and the West has nothing to compare with the Mid-autumn Festival. And let's not forget the part of Chinese culture I like best—its friendliness. Not all countries are as 7 as China.It's good to enjoy other cultures and to learn from them, but they cannot replace your own culture. It's good to look on the other side of the fence,but 8 you take a good long look. You will find that the grass isn't always greener on the other side of the fence.( )1.A.word B.saying C.sentence( )2.A.that B.when C.which( )3.A.that B.if C.why( )4.A.however B.besides C.instead( )5.A.and B.so C.but( )6.A.still B.never C.always( )7.A.warm B.hot C.cold( )8.A.make up B.make up of C.make sureⅡ.[2019·威海改编]还原短文请阅读下面短文,根据短文内容,从方框内所给的选项中选出能填入空白处的最佳选项,使短文意思通顺。
立体几何初步(限时训练30’)答案
1. A2. D3. B【解析】若任取三点都共线，则有 4 个点都共线，与题设不符4. D【解析】这个几何体为如图所示的直三棱锥，高为 1．∴ V =61. 5. D 6. 32321S S S ．【解析】设三条侧棱长分别为 a ，b ，c ，则 21ab = S 1，21bc = S 2，21ca = S 3． 三式相乘，得81a 2 b 2 c 2 = S 1S 2S 3． ∴ abc = 23212S S S ．∵ 三侧棱两两垂直，∴ V =31(21ab )·c =31abc ·21 =313212S S S ．7. 证明：连接D 1E ，D 1F ，并分别延长，使D 1F 与DC 的延长线交于点H ，D 1E 的延长线与DA 的延长线交于点G ．∵ D 1，E ，F 三点不共线，∴ D 1，E ，F 确定一个平面 ．∴ G ，H ∈α．又∵点 E 是AA 1的中点，∴EA 21DD 1，∴ 点 A 是DG 的中点． 同理可得，点 C 是DH 的中点．∴ CH = BC = BA = GA ． 又∵ 四边形 ABCD 是正方形，∴ ∠BCH =∠BAG = 90°．连接BH ，BG ．∴ △BCH ，△GAB 是全等的等腰直角三角形． ∴ ∠CBH =∠ABG = 45°．∴ ∠GBA +∠ABC+∠CBH = 180°． ∴ G ，B ，H 三点共线．又G ，H ∈α，∴ GH ⊂α，而B ∈GH ，∴ B ∈α．∴ D 1，E ，F ，B 四点共面．2. 证明：∵ α∩β= a ，α∩γ= b ，∴ a ⊂ β，b ⊂γ．又∵ a ∩b = O ，∴ O ∈a ，O ∈b ．∴ O ∈β，O ∈γ． ∴ 点 O 在 β，γ的交线 c 上．∴ 三条直线 a ，b ，c 相交于点 O ．8. 证明：取PD 的中点为Q ，连接AQ ，QN ， ∵ 点 N 为PC 的中点，∴ QN 21DC ， A M BCND Q P∴QN AM，∴四边形AMNQ为平行四边形，∴MN∥AQ，∴MN∥平面P AD．。
限时组合训练30套答案
一、答案 :1-5 GBADF二、1.have disappeared结合时间状语可以看出disappear这个动作已经完成,故使用现在完成时态。
2.The most famous 此处暗含最高级,意为“在这些动物之中最有名的是……”。
3.tens tens of millions同tens of thousands 都是固定用法。
4.before 此处是指恐龙比人类诞生早很久。
5.to find be surprised to do sth.意为“做某事感到吃惊”。
6.like 此处like为介词,表示“像……一样”。
7.were joined the way为先行词,省略了where或in which,此句话中主语为the bones,复数,与join的关系为被动。
8.out die out 为固定搭配,意为“灭绝”。
9.too 此处为too...to...结构,表示“太……而不能……”10.have died 从句中的recently可以看出此处用现在完成时。
三、One day last month,a group of Chinese arrived in Brisbane.I was one of them.After goodbye to my dear parents at Beijing Airport,I started my long journey.That was my first journey abroad!How I feltwhen I got on board.We left Shanghai Hong Kong to change to another plane to Melbourne, second largest city in Australia.From there we flew to Brisbane, is the capital city of Queensland,Australia.We were exchange students and to the country by government to learn English in Brisbane for twelve months. From the firstfew lessons, We found the teachers there really worked , and I am sure of everything will go well in the next months.一、答案 :1-5DGACF二、1.1960s 1960s是一种年代的表达方式,意为“20世纪60年代”。
2014年高中语文新课标第二轮总复习限时训练(23-30) 专题五 文学类文章阅读
2014年高中语文新课标第二轮总复习专题五文学类文章阅读限时训练卷(23)限时：35分钟满分：38分一、语言文字运用(12分，每小题3分。
限时6分钟)1.下列词语书写有错误的一项是()A．觊觎蹿红功亏一篑金玉其外，败絮其中B．临摹搏弈披沙捡金如切如磋，如琢如磨C．睥睨急躁韦编三绝盛名之下，其实难副D．踯躅坐落人情世故差之毫厘，谬以千里2.下列各句中，加点的词语使用恰当的一句是()A．美国高官最近频繁表态，不断炒作“中国军方黑客”，声称美国是网络安全方面的受害者，这显然是失之．．公允的。
B．2013年年初我国许多地区被雾霾笼罩，不单．．是政府，每个公民都应增强环保意识，否则，中国环境问题前景堪忧。
C．我们很难确定地说，李安是大陆的，李安是台湾的，或李安是美国的。
他仿佛都是，但也仿佛都不是，他游走于三界之外，在三个板块中翻云覆雨．．．．。
D．国务院总理李克强在新一届国务院第一次全体会议上强调，各部门要限期完成职能转变任务，要彻底改头换面．．．．，绝不能“换汤不换药”。
3.下列各句中，没有．．语病的一句是()A．从无到有，中国航母出现在东方的海平面上。
从试航、改装到正式入列，“辽宁舰”迈出的这一步，注定是中国航母从梦想走向现实的一大步。
B．多年来，我们的专家、学者一再告诫我们，到了冬天，如果不适当地饮酒，就会影响我们对寒冷的抵抗能力。
C．为确保选拔质量，经过严格考察，确认无合适人选的职位，可以空缺。
对公开选拔任用的干部实行试用期制。
D．这不仅反映在教育行政管理的混乱和不公，更表现了价值体系的崩溃：努力与回报相分离，手段与目的相分离。
4.下列选项中的诗句填入《寄人》一诗画横线处，恰当的一项是()别梦依依到谢家，小廊回合曲阑斜。
______________，犹为离人照落花。
A．春月多情如明珠B．有情春月含羞避C．明月空中最有情D．多情只有春庭月二、古诗文默写(5分，每空1分。
限时4分钟)5.(1)女也不爽，________________。
九年级英语限时训练(附参考答案)
九年级英语限时训练（附参考答案）（满分30分时间30分钟）一．根据句意及首字母和汉语提示，完成句子。
（每小题2分，共10分）1. The man was d________ out of the club because of breaking the rule.2. As they were out of work, Mr and Mrs Black had to turn to their r________for help.3. Almost all the animals have their special ways to protect themselves from their e________.4. On rainy days, I have n________to go. So I have no choice but to stay at home and watch TV.5. Their b________ towards me shows that they do not like me at all.二．阅读理解（每小题2分，共10分）Reduce schoolwork burden(负担)on primary and junior high school students. The policy calls for reducing homework and after-school classes. According to the policy, children below the third grade will not have homework anymore. It In July, China introduced the “double reduction (双减)” policy. It hopes to should take no more than 90 minutes for junior high school students to finish their homework. After-school training institutions are not allowed to offer extra education courses or advanced(超前的)teaching on weekends, holidays or during winter and summer vacations. One month has passed since the new semester began. How do students feel about this new policy?“Our homework is clearly less than before,” said 13-year-old Shen Yuzhe from Beijing. “We are not encouraged to buy wor kbooks anymore. The exercises are mainly from the textbook.”According to Shen, students have enough time to process new knowledge now. “Our teachers are also giving us more chances to do experiments and learn from real life,” said Shen. “For example, we went to research earthworms(蚯蚓)in a field during a biology class. This is a much better way to learn things than just hitting the books.”For 13-year-old Zhang Hangming from Tianjin, the best thing about “double reduction” is the increased time in after-sc hool activities. “We can now spend more time taking part in clubs and activities, such as dancing, volleyball and drama. I have joined a group called “leadership development” where I can learn all kinds of skills beyond schoolwork,” said Zhang.Both Shen a nd Zhang find there are fewer exams now. But they think it’s not necessarily a good thing. “Exams push me to study harder. Each exam shows my progress as well as my weak points,” Zhang said.Shen also pointed out that when burden is lightened, self-discipline(自律) becomes the key. “Some students now spend more time having fun when homework is finished early. But if you use all the free time to relax, you might fall behind other students,” he said. “6. The “double reduction(双减)” policy aims to ________.A. make vacations longer for studentsB. reduce the pressure put on teachersC. reduce students’ schoolwork burdenD. help students become more competitive7. Which of the following is TRUE about the policy?A. Homework is not allowed for primary students.B. Junior high schools should reduce their homework.C. All after-school training institutions are asked to close.D. After-school training institutions should offer advanced teaching.8. According to the “double reduction(双减)” policy, what kind of after-school classes CANNOT students take during vacations?A. Sports.B. Math.C. Public speaking.D. Computer programming.9. Which of the following is NOT true about Shen Yuzhe and Zhang Hangming?A. They have less homework and fewer exams now.B. They can spend more time in after-school activities.C. They think the best thing is to have fewer exams now.D. They have more chances to learn knowledge from real life.10. What do Shen and Zhang mainly want to tell us in the last two paragraphs?A. Students should learn to be self-discipline.B. Students should use all the free time to relax.C. Exams aren’t necessary because they only show students’ weak points.D. Students should spend more time having fun after finishing homework.三．阅读表达。
物理计算题限时训练7
物理计算题限时训练（七）（限时30分钟）23．（16分））右下图为示波器的部分构造示意图，真空室中阴极K 不断发出初速度可忽略的电子，电子经电压为U 0的电场加速后，由孔N 沿长为I 、相距为d 的两平行金属板A 、B 间的中心轴线进入两板间，电子穿过A 、B 后最终可打在中心为O 的荧光屏CD 上。
若在AB 间加上变化规律为max 2cos AB U U t T π⎛⎫= ⎪⎝⎭的交变电压，恰好能让t ＝0时刻进入AB 间的电子经A 板右边缘射出打在荧光屏上。
假设在电子通过两板的极短时间内AB 间电场可视为恒定不变。
已知电子电荷量为e ，质量为m ，电子所受重力不计。
求：(1)电子通过孔N 时的速度大小v 0；(2)A 、B 间电压的最大值Umax 和有效值U 。
的半圆形光滑轨道。
现在A 、B 两个小物体之间夹一个被压缩的弹簧(弹簧未与A 、B 挂接)后用细线拴住，使其静止在轨道ab 上。
当烧断细线后，A 物体被弹簧弹开，此后它恰能沿半圆形轨道通过其最高点c 。
已知A 和B 的质量分别为m A ＝0．1 kg 和m B ＝0．2kg ，重力加速度g 取10 m ／s 2，所有物体均可视为质点。
求：(1)A 在半圆形轨道的最高点c 处时的速度大小；(2)A 刚过半圆形轨道最低点b 时，对轨道的压力大小；(3)烧断细线前，弹簧的弹性势能。
25、(20分)如图甲所示，间距为L、电阻不计的光滑导轨固定在倾角为θ的斜面上。
在MNPQ矩形区域内有方向垂直于斜面的匀强磁场，磁感应强度为B；在CDEF矩形区域内有方向垂直于斜面向下的磁场，磁感应强度B t随时间t变化的规律如图乙所示，其中B t的最大值为2B。
现将一根质量为M、电阻为R、长为L的金属细棒cd跨放在MNPQ区域间的两导轨上并把它按住，使其静止。
在t＝0时刻，让另一根长也为L的金属细棒ab从CD上方的导轨上由静止开始下滑，同时释放cd棒。
已知CF长度为2L，两根细棒均与导轨良好接触，在ab从图中位置运动到EF处的过程中，cd棒始终静止不动，重力加速度为g；t x是未知量。
2020中考英语30分钟限时训练 完形+还原短文+阅读填表格+词语运用
完形+还原短文+阅读填表格+词语运用(限时:30分钟)Ⅰ.完形填空I was never very tidy, yet my roommate Kate was very organized. Each of her objects had its place, but mine always hid somewhere. She even labeled(贴标签) everything. I always looked for everything. Over time, Kate got tidier and I got 1 . She would push my dirty clothing over, and I would lay my books on her tidy desk. Both of us can't 2 each other.War broke out one evening. Kate came into the roo m. Soon, I heard her shouting, “ 3 your shoes!” At the same time, I saw my shoes flying at me. I jumped to my feet and started yelling. She yelled back louder.The room was filled with 4 . We could not have stayed together for a single minute until her phone rang. Kate answered it. From her end of the conversation, I could tell right away her grandma was seriously ill. 5 she hung up, she quickly crawled(爬) under her covers, starting to cry.Obviously, that was something she should not go through 6 . All of a sudden, a warm feeling of sympathy(同情) rose up in my heart.Slowly, I 7 the pencils, made my bed and swept the floor, even on her side. I was too busy with my work to notice that Kate had sat up. She was watching, her tears dried and her 8 was such disbelief. I looked up into her eyes. She smiled at me, “Thanks.”Kate and I stayed roommates for the rest of the year. Though we didn't always agree, we learned the key to living together: giving in, cleaning up and holding on.( )1.A.messier B.earlier C.happier( )2.A.hear B.hurt C.stand( )3.A.Take off B.Put away y out( )4.A.anger B.joy C.fear( )5.A.Although B.Unless C.When( )6.A.again B.alone C.already( )7.A.collected B.bought C.dropped( )8.A.decision B.expression C.conditionⅡ.还原短文请阅读下面短文,根据短文内容,从方框内所给的选项中选出能填入空白处的最佳选项,使短文意思通顺。
【导与练】2021版高考英语二轮专题能力提升限时训练 单项填空+任务型读写（含解析）(1)
能力提升限时训练单项填空+任务型读写(限时30分钟)Ⅰ.单项填空(对应学生用书第135页)1.—Shall we have a discussion about how to spend the coming New Year?—(2021皖南八校联考)A.You are right.B.Don’t bother me!C.That sounds great.D.Have a good time!2.Jack,can you tell me you are always late for school recently?(2021合肥一中最后一模)A.Why is it thatB.When is it thatC.What is it thatD.Why it is that3.Mrs.Brown always told her children to be good,warning them to trouble.(2021皖南八校联考)A.live up toB.keep out ofC.put up withD.take part in4.—Mrs.Brown,I wonder if I could take the weekend off?—?It’s slightly difficult with so many people away on holiday,you know.A.Why are you doing soB.Do you really have toC.Where are you goingD.Do you feel it good5.The boss suggested to Jessica strongly that she should have a go od time,but didn’t help.A.whichB.sheC.heD.it6.I’d rather you did some social research when you are free,but you .A.didn’tB.weren’tC.wouldn’tD.don’t7.Bill Gates was so nice that he decided to ninety percent of his money to the charities.A.give upB.give awayC.give outD.give off8.When children start smoking,they don’t realize that they are risking their health.A.to damageB.damagingC.to be damageD.being damaged9.The 15:30 train to Sheffield has been called off situations beyond our control.A.in terms ofB.due toC.according toD.in spite of10.He devoted himself so entirely to his research that he made himself ill.A.unfortunatelyB.purposefullyC.hopefullyD.eventually11.—Would you like out with me this evening?—I’m sorry,but I don’t feel like out today.A.to hang;goingB.hanging;to goC.to hang;to goD.hanging;going12. his injury,Ricardo will play in Saturday’s match with his teammates.A.Instead ofB.In spite ofC.Thanks toD.Due to13.I would appreciate if you could let me know in advance whether or not you will be coming.A.itB.youC.thisD.that14. bad weather stops me,I take exercise outdoors every morning.A.UnlessB.SinceC.IfD.Though15.They will give the award to devotes themselves to the protection of wildlife.A.whoB.anyoneC.whomeverD.whoever答案及剖析:1.C 考查交际用语。
2020年秋苏科版七年级上册第二章《有理数》中的动点问题培优训练(一)
2020年秋苏科版七上第二章《有理数》中的动点问题培优训练（一）培优训练小练习（一）：限时30分钟1．已知数轴上两点A、B对应的数分别为﹣1、3，点P为数轴上一动点，其对应的数为X．（1）若点P到点A、点B的距离相等，请直接写出点P对应的数X；（2）数轴上是否存在点P，使点P到点A、点B的距离之和为18？若存在，请直接写出x的值；若不存在，说明理由．（3）点A、点B分别以2个单位长度/分、1个单位长度/分的速度向右运动，同时点P 以18个单位长度/分的速度从O点向左运动．当遇到A时，点P立即以同样的速度向右运动，并不停地往返于点A与点B之间，求当点A与点B重合时，点P所经过的总路程是多少？2．如图，在数轴上，点A表示﹣10，点B表示11，点C表示18．动点P从点A出发，沿数轴正方向以每秒2个单位的速度匀速运动；同时，动点Q从点C出发，沿数轴负方向以每秒1个单位的速度匀速运动．设运动时间为t秒．（1）当t为何值时，P、Q两点相遇？相遇点M所对应的数是多少？（2）在点Q出发后到达点B之前，求t为何值时，点P到点O的距离与点Q到点B 的距离相等；（3）在点P向右运动的过程中，N是AP的中点，在点P到达点C之前，求2CN﹣PC 的值．3．小刚运用本学期的知识，设计了一个数学探究活动．如图1，数轴上的点M，N所表示的数分別为0，12．将一枚棋子放置在点M处，让这枚棋子沿数轴在线段MN上往复运动（即棋子从点M出发沿数轴向右运动，当运动到点N处，随即沿数轴向左运动，当运动到点M处，随即沿数轴向右运动，如此反复…）．并且规定棋子按照如下的步骤运动：第1步，从点M开始运动t个单位长度至点Q1处；第2步，从点Q1继续运动2t个单位长度至点Q2处；第3步，从点Q2继续运动3t个单位长度至点Q3处…．例如：当t＝3时，点Q1，Q2，Q3，的位置如图2所示．解决如下问题：（1）如果t＝4，那么线段Q1Q3＝；（2）如果t＜4，且点Q3表示的数为3，那么t＝；（3）如果t≤2，且线段Q2Q4＝2，那么请你求出t的值．4．如图，将一条数轴在原点O和点B处各折一下，得到一条“折线数轴”．图中点A表示﹣10，点B表示10，点C表示18，我们称点A和点C在数轴上相距28个长度单位．动点P从点A出发，以2单位/秒的速度沿着“折线数轴”的正方向运动，从点O运动到点B期间速度变为原来的一半，之后立刻恢复原速；同时，动点Q从点C出发，以1单位/秒的速度沿着数轴的负方向运动，从点B运动到点O期间速度变为原来的两倍，之后也立刻恢复原速．设运动的时间为t秒．问：（1）动点P从点A运动至C点需要多少时间？（2）P、Q两点相遇时，求出相遇点M所对应的数是多少；（3）求当t为何值时，P、O两点在数轴上相距的长度与Q、B两点在数轴上相距的长度相等．5．已知如图，在数轴上有A，B两点，所表示的数分别为﹣10，﹣4，点A以每秒5个单位长度的速度向右运动，同时点B以每秒3个单位长度的速度也向右运动，如果设运动时间为t秒，解答下列问题：（1）运动前线段AB的长为；运动1秒后线段AB的长为；（2）运动t秒后，点A，点B运动的距离分别为和；（3）求t为何值时，点A与点B恰好重合；（4）在上述运动的过程中，是否存在某一时刻t，使得线段AB的长为5，若存在，求t 的值；若不存在，请说明理由．培优训练小练习（二）：限时30分钟6．已知M、N在数轴上，M对应的数是﹣3，点N在M的右边，且距M点4个单位长度，点P、Q是数轴上两个动点；（1）直接写出点N所对应的数；（2）当点P到点M、N的距离之和是5个单位时，点P所对应的数是多少？（3）如果P、Q分别从点M、N出发，均沿数轴向左运动，点P每秒走2个单位长度，先出发5秒钟，点Q每秒走3个单位长度，当P、Q两点相距2个单位长度时，点P、Q对应的数各是多少？7．如图，点A、B在数轴上表示的数分别为﹣12和8，两只蚂蚁M、N分别从A、B两点同时出发，相向而行．M的速度为2个单位长度/秒，N的速度为3个单位长度/秒．（1）运动秒钟时，两只蚂蚁相遇在点P；点P在数轴上表示的数是；（2）若运动t秒钟时，两只蚂蚁的距离为10，求出t的值（写出解题过程）．8．（1）在数轴上标出数﹣4.5，﹣2，1，3.5所对应的点A，B，C，D；（2）C，D两点间距离＝；B，C两点间距离＝；（3）数轴上有两点M，N，点M对应的数为a，点N对应的数为b，那么M，N两点之间的距离＝；（4）若动点P，Q分别从点B，C同时出发，沿数轴负方向运动；已知点P的速度是每秒1个单位长度，点Q的速度是每秒2个单位长度，问①t为何值时P，Q两点重合？②t为何值时P，Q两点之间的距离为1？9．已知快递公司坐落在一条东西走向的街道上，某快递员从快递公司取件后在这条街道上送快递，他先向东骑行1千米到达A店，继续向东骑行2千米到达B店，然后向西骑行5千米到达C店，最后回到快递公司．（1）以快递公司为原点，以向东方向为正方向，用1厘米表示1千米，画出数轴，并在数轴上表示出A，B，C三个店的位置．（2）C店离A店有多远？（3）快递员一共骑行了多少千米？10．已知在纸面上有一数轴，折叠纸面．（1）若1表示的点与﹣1表示的点重合，则﹣2表示的点与数表示的点重合（2）若﹣2表示的点与4表示的点重合，回答以下问题：①数7对应的点与数对应的点重合；②若数轴上A、B两点之间的距离为2019（点A在B的左侧），且A、B两点经折叠后重合，求A、B两点表示的数是多少？（3）点C在数轴上，将它向右移动4个单位，再向左2个单位后，若新位置与原位置到原点的距离相等，则C原来表示的数是多少？请列式计算，说明理由．培优训练小练习（三）：限时30分钟11．一辆货车从百货大楼出发负责送货，向东走了4千米到达小明家，继续走了1千米到达小红家，又向西走了10千米到达小刚家，最后回到百货大楼．（1）以百货大楼为原点，以向东的方向为正方向，用1个单位长度表示1千米，请你在数轴上表示出小明、小红、小刚家的位置；（2）小明家与小刚家相距多远？12．已知A、B在数轴上对应的数分别用+2、﹣6表示，P是数轴上的一个动点．（1）数轴上A、B两点的距离为．（2）当P点满足PB＝2PA时，求P点表示的数．（3）将一枚棋子放在数轴上k0点，第一步从k点向右跳2个单位到k1，第二步从k1点向左跳4个单位到k2，第三步从k2点向右跳6个单位到k3，第四步从k3点向左跳8个单位到k4．①如此跳6步，棋子落在数轴的k6点，若k6表示的数是12，则k o的值是多少？②若如此跳了1002步，棋子落在数轴上的点k1002，如果k1002所表示的数是1998，那么k0所表示的数是（请直接写答案）．13．如图，一个点从数轴上的原点开始，先向右移动3个单位长度，再向左移动5个单位长度，可以看到终点表示的数是﹣2．已知点A是数轴上的点，完成下列各题：（1）如果点A表示的数是3，将点A先向左移动7个单位长度，再向右移动5个单位长度，那么终点B表示的数是，A、B两点间的距离为；（2）如果点A表示的数是﹣4，将点A先向右移动168个单位长度，再向左移动256个单位长度，那么终点B表示的数是，A、B两点间的距离为；一般地，如果点A表示的数是m，将点A先向右移动n个单位长度，再向左移动t个单位长度，那么终点B表示的数是，A、B两点间的距离为．14．如图，A、B分别为数轴上的两点，A点对应的数为﹣5，B点对应的数为55，现有一动点P以6个单位/秒的速度从B点出发，同时另一动点Q恰好以4个单位/秒的速度从A点出发：（1）若P向左运动，同时Q向右运动，在数轴上的C点相遇，求C点对应的数．（2）若P向左运动，同时Q向左运动，在数轴上的D点相遇，求D点对应的数．（3）若P向左运动，同时Q向右运动，当P与Q之间的距离为20个单位长度时，求此时Q点所对应的数．15．如图，在数轴上点A表示的有理数为﹣6，点B表示的有理数为6，点P从点A出发以每秒3个单位长度的速度在数轴上由A向B运动，当点P到达点B后立即返回，仍然以每秒3个单位长度的速度运动至点A停止运动，设运动时间为t（单位：秒）（1）求t＝1时点P表示的有理数；（2）求点P与点B重合时的t值；（3）在点P沿数轴由点A到点B再回到点A的运动过程中，求点P与点A的距离；（用含t的代数式表示）（4）当点P表示的有理数与原点的距离是3个单位长度时，直接写出所有满足条件的t 值．参考答案1．解：（1）∵1﹣（﹣1）＝2，2的绝对值是2，1﹣3＝﹣2，﹣2的绝对值是2，∴点P对应的数是1．（2）当P在AB之间，PA+PB＝18（不可能有）当P在A的左侧，PA+PB＝﹣1﹣x+3﹣x＝18，得x＝﹣8；当P在A的右侧，PA+PB＝x﹣（﹣1）+x﹣3＝18，得x＝10．故点P对应的数为﹣8或10；（3）设经过x分钟点A与点B重合，根据题意得：2x＝4+x，解得x＝4．则18x＝18×4＝72．答：点P所经过的总路程是72个单位长度．2．解：（1）根据题意得2t+t＝28，解得t＝，∴AM＝＞10，∴M在O的右侧，且OM＝﹣10＝，∴当t＝时，P、Q两点相遇，相遇点M所对应的数是；（2）由题意得，t的值大于0且小于7．若点P在点O的左边，则10﹣2t＝7﹣t，解得t＝3．若点P在点O的右边，则2t﹣10＝7﹣t，解得t＝．综上所述，t的值为3或时，点P到点O的距离与点Q到点B的距离相等；（3）∵N是AP的中点，∴AN＝PN＝AP＝t，∴CN＝AC﹣AN＝28﹣t，PC＝28﹣AP＝28﹣2t，2CN﹣PC＝2（28﹣t）﹣（28﹣2t）＝28．3．解：（1）当t＝4时，Q1表示的数为4，Q1Q2＝4×2＝8，Q2表示的数为4+8＝12，Q2Q3＝4×3＝12，Q3所表示的数为0，∴Q1Q3＝4，故答案为：4．（2）①当Q3未到点N返回前，有t+2t+3t＝3，解得：t＝，②当Q3点到达N返回再到表示3的位置，t+2t+3t+3＝12×2，解得：t＝，故答案为：或；（3）①当Q4未到点N，有3t+4t＝2，解得：t＝；②当Q4到达点N返回且在Q2的右侧时，有24﹣10t﹣3t＝2，解得：t＝；③当Q4到达点N返回且在Q2的左侧时，有3t﹣（24﹣10t）＝2，解得：t＝2；答：t的值为或或2．4．解：（1）点P运动至点C时，所需时间t＝10÷2+10÷1+8÷2＝19（秒），（2）由题可知，P、Q两点相遇在线段OB上于M处，设OM＝x．则10÷2+x÷1＝8÷1+（10﹣x）÷2，解得x＝．故相遇点M所对应的数是．（3）P、O两点在数轴上相距的长度与Q、B两点在数轴上相距的长度相等有4种可能：①动点Q在CB上，动点P在AO上，则：8﹣t＝10﹣2t，解得：t＝2．②动点Q在CB上，动点P在OB上，则：8﹣t＝（t﹣5）×1，解得：t＝6.5．③动点Q在BO上，动点P在OB上，则：2（t﹣8）＝（t﹣5）×1，解得：t＝11．④动点Q在OA上，动点P在BC上，则：10+2（t﹣15）＝t﹣13+10，解得：t＝17．综上所述：t的值为2、6.5、11或17．5．解：（1）AB＝﹣4﹣（﹣10）＝6，运动1秒后，A表示﹣5，B表示﹣1，∴AB＝﹣1+5＝4．故答案为6，4．（2）运动t秒后，点A，点B运动的距离分别为5t，3t，故答案为5t，3t．（3）由题意：（5﹣3）t＝6，∴t＝3．（4）由题意：6+3t﹣5t＝5或5t﹣（6+3t）＝5，解得t＝或，∴t的值为或秒时，线段AB的长为5．6．解：（1）﹣3+4＝1．故点N所对应的数是1；（2）（5﹣4）÷2＝0.5，①点P在点M的左边：﹣3﹣0.5＝﹣3.5，②点P在点N的右边：1+0.5＝1.5．故点P所对应的数是﹣3.5或1.5．（3）①点P在点Q的左边：（4+2×5﹣2）÷（3﹣2）＝12÷1＝12（秒），点P对应的数是﹣3﹣5×2﹣12×2＝﹣37，点Q对应的数是﹣37+2＝﹣35；②点P在点Q的右边：（4+2×5+2）÷（3﹣2）＝16÷1＝16（秒）；点P对应的数是﹣3﹣5×2﹣16×2＝﹣45，点Q对应的数是﹣45﹣2＝﹣47．7．解：（1）设运动x秒时，两只蚂蚁相遇在点P，根据题意可得：2x+3x＝8﹣（﹣12），解得：x＝4，﹣12+2×4＝﹣4．答：运动4秒钟时，两只蚂蚁相遇在点P；点P在数轴上表示的数为：﹣4；（2）运动t秒钟，蚂蚁M向右移动了2t，蚂蚁N向左移动了3t，若在相遇之前距离为10，则有2t+3t+10＝20，解得：t＝2．若在相遇之后距离为10，则有2t+3t﹣10＝20，解得：t＝6．综上所述：t的值为2或6．故答案为：4；﹣4．8．解：（1）如图所示：（2）CD＝3.5﹣1＝2.5，BC＝1﹣（﹣2）＝3；（3）MN＝|a﹣b|；（4）①依题意有2t﹣t＝3，解得t＝3．故t为3秒时P，Q两点重合；②依题意有2t﹣t＝3﹣1，解得t＝2；或2t﹣t＝3+1，解得t＝4．故t为2秒或4秒时P，Q两点之间的距离为1．故答案为：2.5，3；|a﹣b|．9．解：（1）如图所示：；（2）C店离A店：1﹣（﹣2）＝3千米；（3）快递员一共行了：|1+|+|2|+|﹣5|+|2|＝10千米．10．解：（1）∵折叠后1表示的点与﹣1表示的点重合，∴对折的中心所表示的数为0，∵﹣2到原点0的距离为2，∴只有2到原点0的距离为2，故答案为：2．（2）∵折叠后﹣2表示的点与4表示的点重合∴折叠中心表示的数为（﹣2+4）÷2＝1，①设这个数为m，则有：7﹣1＝1﹣m，解得：m＝﹣5，故答案为：﹣5．②设A表示的数为a，B表示的数为b，由题意得，b﹣1＝1﹣a且b﹣a＝2019，解得，a＝﹣1008.5，b＝1010.5，答：A点表示的数是﹣1008.5，B点表示的数是1010.5．（3）设点C原位置表示的数为c，则点C的新位置表示的数为c+2，根据题意得，c+2＝﹣c，解得，c＝﹣1，答：C原来表示的数是﹣1．11．解：（1）如图：（2）根据（1）可得：小明家与小刚家相距4﹣（﹣5）＝9（千米）．12．解：（1）|+2﹣（﹣6）|＝8，故答案为：8．（2）设点表示的数为x，①当点P在点A的左侧时，有2（2﹣x）＝x﹣（﹣6）解得，x＝﹣，②当点P在点A的右侧时，有x+6＝2（x﹣2），解得，x＝10答：点P所表示的数为﹣或10．（3）①设k0所表示的数为a，由题意得，a+2﹣4+6﹣8+10﹣12＝12，解得，a＝18，答：k0所表示的数为18．②由题意的，a+2﹣4+6﹣8+10﹣12+…+2002﹣2004＝1998，解得，a＝3000，故答案为：3000．13．解：（1）∵点A表示数3，∴点A向左移动7个单位长度，再向右移动5个单位长度，终点B表示的数是3﹣7+5＝1，A，B两点间的距离是|3﹣1|＝2，故答案为1，2；（2）∵点A表示数﹣4，∴将A点向右移动168个单位长度，再向左移动256个单位长度，那么终点B表示的数是﹣4+168﹣256＝﹣92，A、B两点间的距离是|﹣4+92|＝88；故答案为﹣92，88；∵A点表示的数为m，∴将A点向右移动n个单位长度，再向左移动t个单位长度，那么点B表示的数为（m+n﹣t），A，B两点间的距离为|n﹣t|，故答案为m+n﹣t，|n﹣t|．14．解：（1）设运动时间为x秒，4x+6x＝55﹣（﹣5），解得：x＝6，因此C点对应的数为﹣5+4×6＝19，（2）设运动时间为y秒，6y﹣4y＝55﹣（﹣5），解得：y＝30，点D对应的数为﹣5﹣4×30＝﹣125，（3）①相遇前PQ＝20时，设运动时间为a秒，4a+6a＝55﹣（﹣5）﹣20，解得：a＝4，因此Q点对应的数为﹣5+4×4＝11，②相遇后PQ＝20时，设运动时间为b秒，4b+6b＝55﹣（﹣5）+20，解得：b＝8，因此C点对应的数为﹣5+4×8＝27，故Q点对应的数为11或27．15．解：（1）当t＝1时3×1＝3﹣6+3＝﹣3所以点P所表示的有理数是﹣3；（2）当点P与点B重合时，点P所运动的路程为|6﹣（﹣6）|＝12所以t＝12÷3＝4；（3）点P沿数轴由点A到点B再回到点A的运动过程中，点P与点A的距离分为2种情况：当点P到达点B前点P与点A的距离是3t（0≤t＜4）；当点P到达点B再回到点A的运动过程中点P与点A的距离是：24﹣3t（4≤t≤8）；（4）当点P表示的有理数与原点（设原点为O）的距离是3个单位长度时，则有以下四种情况：当点P由点A到点O时：OP＝AO﹣3t，即：6﹣3t＝3，∴t＝1；当点P由点O到点B时：OP＝3t﹣AO，即：3t﹣6＝3，∴t＝3；当点P由点B到点O时：OP＝18﹣3t，即：18﹣3t＝3，∴t＝5；当点P由点O到AO时：OP＝3t﹣18，即：3t﹣18＝3，∴t＝7，即：当点P表示的有理数与原点的距离是3个单位长度时，t的值为1或3或5或7．。
2020中考英语30分钟限时训练 完形+还原短文+回答问题+词语运用
完形+还原短文+回答问题+词语运用(限时:30分钟)Ⅰ.完形填空Mrs. Wettiner was old and blind. But she tried to do everything for herself. She even used to go for walks alone from her home once a day for exercise and fresh air, and found her way by 1 things with her white stick. She learnt where everything was, so she never lost her way. But then one day some men came and 2 some trees at the side of the road which she followed. When she reached that place that evening, she didn't feel the trees with her stick, so she was in 3 .She stopped for a minute and shouted, but she didn't hear any other people, so she went ahead for a kilometer or two, and then she heard water 4 her.“Water?” she said aloud, and stopped. “Am I 5 ? I suppose so. I must be on a bridge, and there must be a river under me. I've been told that there's a river in this part of the country. But I don't know its exact position(位置). How am I going back to my home from here?”Suddenly she heard a young man's friendly voice near her. It said, “Excuse me, can I help you?”“How kind of you!” Mrs. Wettiner answered 6 . “Yes, please. I'm lost. Some of the trees which I follow when I go for my evening walk were removed today, and if I am not lucky enough to meet you, I don't know what to do. Can you please help me to get home?”“Certainly,” the man answered. “Where do you live?”Mrs. Wettiner told him, and they began walking. The man took Mrs. Wettiner to her home, and she 7 him in and gave him some coffee and a piece of cake. She told the man how 8 she was that she had met him.“Don't thank me,” the young man said. “I want to thank you. I was trying to make up my mind to put myself into the river. But I'm not going to do it now.”( )1.A.reading B.touching C.making( )2.A.cut back B.cut up C.cut down( )3.A.trouble B.happiness C.control( )4.A.above B.under C.over( )5.A.tired B.busy C.lost( )6.A.happily B.patiently C.proudly( )7.A.ordered B.joined C.invited( )8.A.careful B.thankful C.harmfulⅡ.[2019·绍兴改编]还原短文请阅读下面短文,根据短文内容,从方框内所给的选项中选出能填入空白处的最佳选项,使短文意思通顺。
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1.故选 C.
5
x2 y2
评注
双曲线
a2
b2
1a 0,b 0 的一个焦点到其渐近线的距离（渐焦距）为 b ，做选填题时可直
接利用此结论得出结果.
4. 解析 2 cos 0, 即 cos 1 0 ，所以 0 ，或 cos 1 .化为直角坐标系即为
限时训练（三十）
答案部分
一、 选择题
1
2
3
4
5
6
7
8
B
D
C
C
B
A
D
B
二、 填空题
9. 3
23
10.
3
11. 40
12.10
解析部分
13.1 14. ②③
一、选择题
1. 解析 1 2i a i a i 2ai 2i2 a 2 1 2ai 为纯虚数，
14.解析① y' = 3x2 1, f x 1 有两个相等实根，因此曲线 y x3 x 不具有“可平行性”；
1
1
② y' 1 x2 ，f x a
a ,1
总有两个不同的实根与之对应，因此曲线 y x 是具有“可 x
平行性”的曲线；
③ y' cos x ，则 cos x a a 1,1 至少有两个不同的实根与之对应，因此曲线 y sin x 是具有“可
OE 1 OB 1 OD ，所以 DOC 60 ， C 30 .又 CD 2 ，所以 OD 2
3
4
， OC
3
，
22
3
3
2
23 BC OC OB .
3
D
A
O EB
C
11.解析 依题意，从 6 个数字中任取 3 个，然后将这 3 个数字中最大的数字做为十位数字，其余两个再
平行性”的曲线；
1
④ y' = 2x + 4 ，当 f x 2 2 4 时，只有一个实根 x
2
2
，因此曲线 x 2 ln x 不具有“可
x
2
平行性”.
综上，②③是具有“可平行性”的曲线.
评注 本题将“可平行性”这一抽象的概念转化为曲线对应函数的导函数是否存在 2 个不同的零点的问
3
1
π
3
3
解法二：因为 sin
2
，且
2
,π
，所以 cos
2
, tan
3
.
3
2
2 tan
则 tan 2
3 3.
1 tan2
2
3
1
3
10.解析如图所示，连接 OD ，如图所示.因为 D 为切点，所以 OD CD ，因为 E 为 OB 中点，所以
则 a 2 0 ， a 2 .故选 B.
2. 解析解1 x 0 ，得 x 1，即 M x x 1 ，所以 R M x x 1 .故选 D.
3. 解析由双曲线的对称性，不妨求双曲线的右焦点 5, 0 到渐近线 x 2 y 0 的距离.由点到直线距离
x2 y2 0 ，或 x 1 .故选 C.
5.解析如图所示，由约束条件作出可行域如图所示，
要使得 tan AOB 最大，则 AOB 取最大，
即 A 1, 2 ， B 2,1 为所求，此时
1
tan AOB
2 2
3 . 故选 B.
1 1 2
4
2
y
A B
x-3y+1=0
排列，所以“组合数”有
C36
A
2 2
40 个.
12.解析 2a3 a2a4 a32 ， a3 0 ，所以 a3 2 .又 b3 a3 ，所以 b3 2 .因为数列bn 为等差数列，所
以 S5 5b3 5 2 10 .
13.解析 由已知 f 1 0 ，所以 f f 1 f 0 0 a 3t2dt a3 1，解得 a 1. 0
8. 分析 PE AC 0 ，过 E 作与 AC 垂直的平面，设该平面截四棱锥所得的图形即为动点 P 的轨迹.
解析 如图所示，取 SC ，DC 的中点 M ，F ，则 EF //BD ，ME//SB ，所以平面 SBD// 平面 MEF ，
而 AC 平面 SBD ，所以 AC 平面 MEF ，则动点 P 在四棱锥表面上运动的轨迹为△ MEF ，则动