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聚碳酸酯的透光率良好，可制作挡风玻璃、眼镜片等．某聚碳酸酯（M）的合成路线如图： 已知： Ⅰ．D的分子式为C3H4O3，核磁共振氢谱只有一组峰 Ⅱ．R1COOR2+R3OHR1COOR3+R...
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高三下学期化学《》真题及答案
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下列关于采光顶用聚碳酸酯板阳光板的叙述错误的是
耐候性不小于25年
双层板透光率不小于80%
单层板材厚度3~10mm
耐温限度-40~120℃
为扩大视野面窗空气呼吸器面罩的面窗镜片采用材料
橡胶
玻璃
聚碳酸酯
硅胶
对紫外线阻挡作用较差的镜片是
标准树脂（CR39）镜片
聚碳酸酯（P镜片
透明玻璃镜片
高折射率树脂镜片
高折射率玻璃镜片
消防护目镜的镜片通常采用材料镜片内侧具有防雾涂层外侧具有防刮 涂层并且具有较高的紫外线吸收率
聚碳酸酯
玻璃
塑胶
木质
聚碳酸酯制板
下列关于采光顶用聚碳酸酯板阳光板的叙述错误的是［2012-092］
单层板材厚度为3~19mm
耐候性不小于25年
双层板透光率不小于80%
耐温限度-40~120℃
灯具的配光类型可分为和路灯一般采用灯具灯头的透光材料采用聚碳酸酯有机玻璃钢化玻璃等
聚碳酸酯的透光性良好可制作车船飞机的挡风玻璃以及眼镜镜片光盘唱片等原来合成碳酸酯的一种原料是用有毒的
二烯类
二醇类
二卤化物
二酚类
以下塑料中透光率92％优于普通硅玻璃的是
氨基塑料
硅酮塑料
聚甲基丙烯甲酯
聚碳酸酯
有机玻璃的原料是
聚碳酸酯
环氧树脂
聚甲基丙烯酸甲酯
酚醛树脂
下列关于采光顶用聚碳酸酯板阳光板的叙述错误的是哪项
单层板材厚度3~10mm
耐候性不小于25年
双层板透光率不小于80%
耐温限度-40~120℃
聚碳酸酯是一种重要的热固性工程塑料
防峰服的面罩主要有三种聚氯乙烯网式聚碳酸酯面罩和不锈钢丝金属网式 与聚碳酸酯复合面罩
防暴警察用头盔聚碳酸酯制
防弹胶PC初级形状聚碳酸酯
聚碳酸脂的透光性良好可制作车船飞机的挡风玻璃以及眼镜镜片光盘唱片等．原来合成聚碳酸酯的一种原料是用
二卤化物
二酚类
二醛类
二烯类
聚碳酸酯PC性能有哪些优缺点
聚碳酸酯的透光性良好可制作车船飞机的挡风玻璃以及眼镜镜片光盘唱片等原来合成碳酸酯的一种原料是用有毒的
二烯类
二醇类
二酚类
二卤化物
聚碳酸酯PP分别为
对紫外线阻挡作用较差的镜片是
聚碳酸酯(PC)镜片
透明玻璃镜片
标准树脂(CR39)镜片
高折射率树脂镜片
高折射率玻璃镜片
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假定你是李华你的美国朋友Bill在春节期间给你发了一封节日问候邮件并在信中问及红色在中国春节中的使用请你给他回封邮件介绍下红色在春节中的使用情况.内容包括以下几点 1.红色在中国的象征 2.春节期间红色的使用至少列出两个要点. 注意1.词数100左右 2.可以适当增加细节以使行文连贯
已知fx＝|ax﹣1|﹣|ax+1|a＞0． Ⅰ求fx的最小值b及最大值c Ⅱ设m＞0n＞0m3+8n3＝c求m+2n的最大值．
Ifyouonlygotsixhours'shuteyelastnightthereisnoneed1losesleepoverit. Scientistssaythatthoughitis2widebelievedthatweneedeighthoursofsleepanightsixtosevenhoursisthenaturalamount. Advisingshort﹣sleeperstoresteasytheUSresearcherssay3haveimportantimplications暗示含义fortheideathatweneedtotakesleepingpillsbecausesleephasbeenreducedfrom4itnaturallevelbythewidespreaduseofelectricityTVtheInternetandsoon.' TheleadauthorofastudyGhandisaidThere'sthe5expectthatweshouldallbesleepingforeightorninehoursanightandifwetookawaymoderntechnologywewouldbesleepingmore.Butnowforthefirsttimeweareshowingthat'snot6truth. Mostofthose7werestudiedsleptforlessthansevenhoursanightwiththeaverageamountjustsixhoursand25minutes.Thisismuchlessthantheeighthoursoften8recommendinwesternsocieties. Despitethisthepeoplestudiedwereingoodhealth9lowerratesofobesity肥胖症betterbloodpressureand10healthyheartsthanpeopleinindustrialisedsocieties.Theywerealsofitter.
Winningliterarycompetitionsdoesn'talwaysleadtofame.Buthavingafewsuchwinstoboastaboutdoesyounoharmwhenapproachingeditorsoragentssoifyouhavedreamsofawritingcareerthesecouldbetheplacetobegin.Belowisalistofthemostinterestingcompetitions.Bearinmindthatcontestswithsmallerprizesattractfewerentriesandarethereforeeasiertowin. WundorEditionsPoetryCompetition WundorEditionsarelookingforcreativewriterstoentertheirlatestpoetrycontest.Ifyouhappentobe16oroversendinapoemonanysubjectrunningtoasmanywordsasyouthinkyoucangetawaywithbeforethejudge'seyesglazeover兴趣丧失. ClosingNov.30.Prize£500.EntryFee£10. Manning'sPitPoetryCompetition Itdoesn'tsoundveryattractivebutitseemsManning'sPitissomethingofabeautyspotwithmorethanitsshareofwildlife.Butit'snowunderthreat.Thiscontestaimsoraisefundstohelpsaveit.Yourtaskistowriteapoemofupto40linesaboutManning'sPitorasimilartreasuredandthreatenedpieceofcountrysidenearatownorvillage. ClosingNov.30.Prizes£100£30£20.EntryFe£3. Commonwealth英联邦ShortStoryCompetition ThiscontestfromCommonwealthWritersisforunpublishedshortfictionofbetween2000and5000wordsaimedatadults.ButyouhavetobeacitizenofaCommonwealthcountry.YoucanwriteyourstoryinEnglishBengaliChinesePortugueseSamoanTamilKiswahiliorMalay. ClosingNo.1.Prize£5000.EntryFee£25. SouthwordFictionChapbookCompetition ToenterthisinternationalcontestfromtheMunsterLiteratureCentreinCorkIrelandyoushouldsubmit10000to15000wordsoffictionintheformofacollectionofshortstories.Storiescanhavebeenpublishedpreviouslyinweborprintjournalsbutnotinastand﹣alonepublicationbytheauthor. ClosingOct.31.PrizesBestInternationalEntryandBestIrishEntry.EntryFee£5forone£10forsix. 1What'sthepurposeoftheliterarycompetitions? A.Toattractmorekidstowritepoems. B.TobringupmoreInternetcelebrities. C.Tomakepeopleknowmoreaboutliterature. D.Toofferaplatformtothosewithwritingdreams. 2WhatisrequiredforparticipantstoenterCommonwealthShortStoryCompetition? A.TheyshouldbeCommonwealthcitizens. B.Theirworksshouldbeupto40lines. C.Theirworksshouldbeaimedatteenagers. D.TheyshouldwritetheirstoriesinEnglish. 3Towhichcontestcanparticipantscontributetheirwebfictions? A.Manning'sPitPoetryCompetition. B.WundorEditionsPoetryCompetition. C.CommonwealthShortStoryCompetition. D.SouthwordFictionChapbookCompetition.
函数fx＝|x|﹣ln|x|若[fx]2﹣mfx+3＝0有8个不相等的实数根则m的取值范围是
Accordingtoanoldstoryafarmeroncefoundthatabagofcornhadbeenstolenfromhishouse.Hewenttothejudgeandtoldhimabouthisloss.Thejudgeorderedallthepeopleofthefarmtocomebeforehim.Hetookanumberofsticksofequallengthandgaveonesticktoeachman. HethensaidComebeforemeagaintomorrow.Ishallthenknowwhichofyouisthethiefbecausethestickgiventothethiefwillbeoneinchlongerthantheothers. Thethiefwasafraidofbeingfoundoutandsohecutaninchoffhisstick.Thenextdaythethief'sstickwasfoundtobeoneinchshorterthananyoftheothers.Inthiswaythethiefwasfoundoutandwasatoncetakenawaytoprison. 1Thejudgegaveeachmanastick. A.tochangebackthefarmer'scorn B.tobeatthethief C.asatooltofindoutthethief D.soastoplayagametogether 2Sincethethiefcutthestickshort. A.hewasfoundout B.thejudgecouldn'tcatchhim C.hisstickhadanequallengthwiththeothers' D.hisstickwouldn'tbeanylonger 3Thewisewaythejudgefoundoutthethiefintheendwastomake. A.thethiefcutthestickoff B.thethiefcutaninchoffthestick C.thestickgrowaninchlonger D.theother'sstickswouldbecomeoneinchshorter
ItseemedlikeatypicalNovemberdaytwoyearsagoaftermygrandmotherhadpassedaway. FeelingtiredandhopelessIbeganwalkingtomy1aftermyshopping.AsIlookedupintotheskyinthepublicparkinglotamillionquestions2mymind.Whydidthishappentome?Aren'twesupposedtoget3fromthepeoplethatpassedaway?WhydidInotfeelher4anymore?Isthereaheaven? 5awomanrolleddownherwindowanddistracted打断myunanswered6.Excusemeexcusemeexcusemeshesaidloudly.ThinkingshewasgoingtoaskformyparkingspotI7pointedtomycar.Noexcusemeshesaidagain. AtthispointIfeltIhadnochoicebuttoseewhatthis8ladywanted.ThenIrealizedthatthiswomanwas9somethinginherbag.SurprisinglyIwas10byasenseofreliefwhentheladywassearching.Underaclutter混乱ofmakeupmoneyandother11shefinallyreachedtotheverybottomofherbagand12meathree﹣pagepamphlet. Ilookeddownatthemysteriousandobviouslyusedpamphletandthefrontcover13WhatHopeforDeadLovedOnes? Ittookmeonlyafewsecondstounderstandthe14withthiswomanbutbythetimeIlookedupshewas15. IfeltasenseofrelaxationasIopenedthefirstpage.Itexplainedhowpeople16buttheirspiritremains.Ifinallyfelthopefromthe17changeinevents.Andthiswasthefirsttime18mygrandmahadleftthatIfelther19me. ItwasacommondayinNovemberwhenmylifeturnedbackaroundandIbegantofeel20again.Itwasamiracle. 1A.school B.home C.car D.seat 2A.runinto B.crowdedinto C.turnedinto D.burstinto 3A.news B.signals C.signs D.advice 4A.presence B.appearance C.courage D.concern 5A.Naturally B.Gradually C.Immediately D.Suddenly 6A.needs B.thoughts C.requests D.words 7A.surely B.still C.simply D.exactly 8A.disappointing B.interesting C.kind D.annoying 9A.searchingfor B.lookingat C.pickingup D.settingdown 10A.overcome B.attracted C.changed D.discouraged 11A.books B.belongings C.keys D.pens 12A.sent B.left C.threw D.handed 13A.forecast B.told C.shared D.read 14A.connection B.exchange C.explanation D.greetings 15A.lost B.left C.gone D.removed 16A.passeddown B.diedaway C.diedoff D.passedaway 17A.surprising B.correct C.crazy D.frightening 18A.as B.before C.because D.since 19A.against B.beyond C.with D.for 20A.satisfaction B.hope C.success D.freedom
函数fx＝ex+m实数m为常数． Ⅰ求gx的最大值 Ⅱ讨论方程的实数根的个数．
TeensandyoungerchildrenarereadingalotlessforfunaccordingtoaCommonSenseMediareportpublishedMonday. Whilethedeclineoverthepastdecadeissteepforteenreaderssomedatainthereportshowsthatreadingremainsabigpartofmanychildren'slivesandindicateshowparentsmighthelpencouragemorereading. Accordingtothereport'skeyfindingstheproportion比例whosaythey‘hardlyever'readforfunhasgonefrom8percentof13﹣year﹣oldsand9percentof17﹣year﹣oldsin1984to22percentand27percentrespectivelytoday.Thereportdatashowsthatpleasurereadinglevelsforyoungerchildrenages2﹣8remainlargelythesame.Buttheamountoftimespentinreadingeachsessionhasdeclinedfromclosertoanhourormoretoclosertoahalfhourpersession. Whenitcomestotechnologyandreadingthereportdoeslittletocounsel建议parentslookingfordataabouttheeffectofe﹣readersandtabletsonreading.Itdoespointoutthatmanyparentsstilllimitelectronicreadingmainlyduetoconcernsaboutincreasedscreentime. Themosthopefuldatasharedinthereportshowsclearevidenceofparentsservingasexamplesandimportantguidesfortheirkidswhenitcomestoreading.Datashowsthatkidsandteenswhodoreadfrequentlycomparedtoinfrequentreadershavemorebooksinthehomemorebookspurchasedforthemparentswhoreadmoreoftenandparentswhosetasidetimeforthemtoread. Astheendofschoolapproachesandschoolvacationreadinglistsloom逼近aheadparentsmighttakethischancetostepinandmaketheirownsummerreadinglistandplanafamilytriptothelibraryorbookstore. 1WhatistheCommonSenseMediareportprobablyabout? A.Children'sreadinghabits. B.Qualityofchildren'sbooks. C.Children'safter﹣classactivities. D.Parent﹣childrelationships. 2Wherecanyoufindthedatathatbestsupportschildrenarereadingalotlessforfun? A.Inparagraph2. B.Inparagraph3. C.Inparagraph4. D.Inparagraph5. 3Whydomanyparentslimitelectronicreading? A.E﹣booksareofpoorquality. B.Itcouldbeawasteoftime. C.Itmayharmchildren'shealth. D.E﹣readersareexpensive. 4Howshouldparentsencouragetheirchildrentoreadmore? A.Actasrolemodelsforthem. B.Askthentowritebookreports. C.Setupreadinggroupsforthem. D.Talkwiththeirreadingclassteachers.
Weallknowthatexerciseisgoodforyourhealth.Butsomekindsofexercisemaybebetterthanothers. Runningforexamplemayhelptoprotectagainstheartdiseaseandotherhealthproblems.Runningmayalsohelpyoulivelonger.Researcherssayitisnotimportanthowfaryourun.Italsodoesnotmatterhowfastorevenhowoftenyourun.AsadvertisementsfortherunningshoesNikesayJustDoIt. Recentlyresearchersstudiedmorethan55000adults.Aboutone﹣fourthoftheadultsreportedrunningregularly.Thestudyfoundtheserunnerswereconsiderablylesslikelythannon﹣runnerstodieofanyformofdiseaseincludingheartdisease.Infacttherunnerslivedonaveragethreeyearslongerthanthenon﹣runners. Thisstudylasted15years.Duringthattimemorethan3400oftheindividualsdied.About1.200ofthedeathswerelinkedtoheartdiseasehearattackorstroke. OneoftheresearchersisamannamedD.C.LeeaprofessorofIowaStateUniversityComparedtonon﹣runnershesaidrunnersshowedamuchlowerriskofdyingfromsomediseases.Comparedtonon﹣runnersrunnersshowed30percentlowerriskofdeathbyanycausesincludingheartattackstrokeandcancer.Alsorunnerscomparedtonon﹣runnersshowed45percentlowerriskofdeathbycardiovasculardiseases心血管疾病includingheartattackandstroke. D.C.Leeandtheotherresearchersfoundthatspeeddistanceandhowoftenonerunsmadelittledifferenceinreducingtheriskofdeath.Therunnersinthestudyaveragedbetween10and16kilometersperhour.MrLeesaidslowerrunnersandthosewhoonlyranonceortwiceaweekwerehelpednearlyasmuchasthosewhoranfasterandfurther.Andalsowelookedattheinningovertimeandwefoundthatpersistentrunnersoversixyearsshowedthebiggestbenefitsaswell. 1WhatdoestheauthormeanbyquotingNike'sadJustDoit? A.It'stimeforyoutostartrunning. B.Nikehasalwayskeptitspromise. C.Youhavetorunasfastaspossible. D.Runningdocsyougoodwhateveritsform. 2Theresearchersgottheresultsoftheirstudymainlyby. A.analyzingdata B.havinginterviews C.doingexperiments D.doingfieldsurvey 3WhatcanwelearnfromParagraph5? A.Heartdiseaseisthebiggestkillerofmankind. B.Runnersaregenerallyhealthierthannon﹣runners. C.Heartdiseasehaskilledmorepeoplethancancer. D.Runninggreatlyreducestheriskofcardiovasculardisease. 4WhatcanweknowaccordingtoMrLee? A.Slowerrunnersandfasterrunnersbenefitequallyfromrunning. B.Youcanbenefitmostifyourspeedisover10kmperhour. C.Youmustcontrolyourspeedproperlywhilerunning. D.Thefurtheryourunthemorebenefitsyouwillget.
设ab是实数则的充要条件是
利用反证法证明若则a＝b＝0应假设
已知函数若函数gx＝fx﹣mx有三个零点则实数m的取值范围是．
假定英语课上老师要求同桌之间交换修改作文请你修改你同桌写的以下作文.文中共有10处语言错误每句中最多有两处.每处错误仅涉及一个单词的增加删除或修改. 增加在缺词处加一个漏字符号∧并在其下面写出该加的词. 删除把多余的词用斜线\划掉. 修改在错的词下面画一横线并在该词下面写出修改后的词. 注意 1.每处错误及其修改均仅限一词 2.只允许修改10处多者从第11处起不计分. Hearingthenewsthatthe2022WinterOlympicswouldbeholdinChinaIfeltveryexcited.ItremindedtomehowIlearnedskatingwhenIwasachild.At7Ibegantogocrazyaboutskating.Inbeginningitwasextremelytoughformetokeepmybalance.IalwaysfalloveronthegroundasaresultofthatIthoughtIhadnotalentforskating.SoIgraduallylostconfidenceandbecameimpatient.ThemoreimpatientIwasthemoreterribleIdid.Iwasabouttogiveupwhilemyfathercametomyassistance.EncouragedbyherIrestoredconfidenceandstoodupagain.AsIpracticedskatinghealwayscreatedarelaxedatmosphereandputforwardsomespecificadvices.EventuallyImadeit.
HermanMelvilethewriterofthefamouswhalestoryMobyDickoncewrotethathumpbackwhaleswerethemostlightheartedofallthewhales.Knowntobeintelligentanimalsandcanbeseenworkingtogethertohuntschoolsofsmallfishhumpbacksareafavoriteofwhalewatcherseverywhere.Andifyoulistencloselyyoumightevenhearonesinging. Marine海洋biologistJimDarlinghasstudiedthesongsofhumpbackwhalesformorethan25years.WhilerecordingwhalesongsonaboatnearHawaiiheinvitedauthorDouglasChadwicktoexperiencedivingwithahumpback.InthewaterChadwickheardthewhale'ssongsinawayheneverheardthembefore.SuddenlyInolongerheardthewhale'svoiceinmyearshesaid.Ifeltitinsidemyheadandbones.WhenswimmingwiththewhaleChadwickcouldseethatthewhalewasawareofhimbutnotalarmedbyhispresence.UpintheboatDarlingrecordedthewhale'ssongwhichcanbelongandcomplexsometimeslastingfor30minutesormore.Actuallytheyareperhapsthelongestsongssungbyanyanimal. Darlingsaysthatonlymalehumpbackssingbutforunknownreasonsitwaspreviouslythoughtthattheysangtoattractfemalesbutscientistsshowedthiswasincorrectwhentheyplayedrecordingsofwhalesongsintheoceanandthefemalewhalesdidnotrespond.Anotherideaisthatmalehumpbackscompetewitheachotherusingsongsjustasothermaleanimalsonlanddousingtheirhornsorsharpteeth. Researchershavealsofoundthathumpbackwhalesongsaredifferentindifferentpartsoftheworldperhapslikewhalenationalsongs.Theymayalsobelikehittunesontheradiochangingovertime﹣﹣﹣﹣fromoneyeartothenextorevenoverasinglebreedingseasonwhentheyproduceyoung. AnothermemberoftheresearchteamphotographerFlipNicklinrecallsaspecialmomenthehadwhileinteractingwithahumpback.Whilehewassnorkeling潜水somedistancefromthehugeanimalitapproachedhimuntilitwasjustafewmetresaway.ItthengentlycarriedNicklintowardsitseyewithaflipper鳍肢asifexaminehim.Obviouslytheurgetounderstandadifferentspeciesgoesbothways. 1Whatisthispassagemainlyabout? A.Howtorecordthehumpbacksintheocean. B.Howhumpbackscommunicatewithpeople. C.Humpbacksongsandwhattheymightmean. D.thecareerofamanwhoisinterestedinhumpbacks. 2Whenthescientistsplayedsongsintheocean. A.thesongsattractedfish B.nofemalewhalescame C.malewhalesbecameangry D.maleandfemalewhalescametogether 3WhatisNOTtrueabouthumpbackwhales? A.Theirsongsareshortandsimple. B.Onlymalehumpbackwhalessing. C.Humpbackwhalesareveryfriendly. D.Theyarepopularwithwhalewatchers. 4WhatdoChadwickandNicklinhaveincommon? A.Theywereafraidofwhales. B.Theyswamwiththewhales. C.Theirjobsaretotakephotosofthewhales. D.Theyaremarinebiologistsstudyingwhales.
Thesenseofhumorisoneofthemostpowerfultoolsyouhaveforgettingridofanysourceofstressinyourlife.1Wecan'tover﹣estimatetheimportanceofthesenseofhumortoomuch.Infactmakingworkfunhelpsemployeesperformbestandprovidequalitywork. 2Tellingjokesandstoriesandusingteam﹣buildinggamesincompaniesmakepeoplehavemorefunatwork.Somecompaniesevenhavetalentshowsorholddanceorsportscompetitions.Itjustgivesemployeesabreakinthedayandachancetolaughatthemselves. 3Humorshouldbeaboutlaughingwithratherthanlaughingatothers.Weallhaveprobablyheardjokesthatseemedtobotherorhurtothers.Forexamplejokesmakingfunofemployeesfortheirweightracereligionetc.arenotonlyharmfultothepersonbutalsocancreateanunfriendlyworkingenvironment. Evenifthejokeswereintendedtobehumoroustheymaynotbereceivedthatway.Ihaveevenheardspeakersmakeslightdirtyjokesontheaudiencethinkingtheywouldbeseenascool.Infacttheaudiencethoughtthespeakershadnotaste.4InanothercaseIheardaboutamanagerwhowasoutpartyingwithco﹣workersandkiddingabouthowthebosslikedcertainpeoplemorethanothers.Suchjokesactuallyhaddamagingeffectsonpeopleinthecompany. Humorifpropercanbrightenuptheworkplaceandreducesomeofthestressweareallexperiencing5 A.Andtheylostpeople'srespectasaresult. B.Ofcourseitisimportanttouseproperhumoratwork. C.Everyoneagreedthattheirworkneededtobemorefun. D.Thereareplentyofwaystobringhumorintotheworkplace. E.Sotakeamomenttolaughandhelpusalltofeelhappieratwork. F.Inadditionlaughtercanbrightenupthefeelingsofeveryonearound. GThemostobviouswaytomakeyourjobfunistolearntofindsomehumor.
Ageingandrobotsaremorecloselyrelatedthanyoumightthink.Youngcountrieswithmanychildrenhavefewrobots.Ageingnationshavelots.ThecountrieswiththelargestnumberofrobotsperindustrialworkerincludeSouthKoreaSingaporeGermanyandJapan.whichhavesomeoftheoldestworkforcesintheworld. Theconnectiondoesnotmerelyreflectthefactthatyoungcountriestendtobepoorandcannotaffordfancymachineswhichtheydonotneedanyway.Itholdsgoodwithinrichcountriestoo.ThosewithrelativelyfewrobotscomparedwiththesizeoftheirworkforceincludeBritainandFrancebothofwhichbyrich﹣countrystandardsareageingslowly. Tworecentstudiesquantifytheconnection.DaronAcemogluofMITandPascualRestrepoofBostonUniversityshowthatbetween1993and2014thecountriesthatinvestedthemostinroboticswerethosethatwereageingthefastestmeasuredasariseintherateofpeopleover56comparedwiththoseaged26﹣55.Theauthorspositaruleofthumbaten﹣pointriseintheirageingrateisassociatedwith0.9extrarobotsperthousandworkers. AstudyfromGermanyuseddifferentmeasuresbutreachedthesameconclusion.Theyfoundthatthegrowthinthenumberofrobotsperthousandworkersrisestwiceasfastasthefallinthegrowthrateofthepopulatione.g.ifpopulationgrowthfallsby1%thegrowthinrobotdensityrisesby2%.Populationgrowthiscloselyrelatedtoagestructure. Thesefindingsshouldnotbesurprising.Robotstypicallysubstituteforlabour.Thatiswhymanypeoplefearthattheywilldestroyjobs.Countrieswithplentyofyoungworkersdonotneedlaboursubstitutes.Wagestherealsotendtobelowmakingautomationunprofitable.Butageingcreatesdemandforautomationintwoways.Firsttopreventoutputfallingasmorepeopleretiremachinesarenecessarytosubstituteforthosewhohavelefttheworkforceortoenableageingworkerstocontinuetodophysicallabour.Secondoncepeoplehaveretiredtheycreatemarketsfornewkindsofautomationincludingrobotsthathelpwiththemedicalandotherrequirementsofcaringforpeoplewhocannolongerlookafterthemselves 1Whatcanweinferfromthearticle? A.Ageingiscloselyrelatedtorobots B.Ageingcountrieshavefewrobots. C.Robotsareneededinyoungcountries. D.Youngandrichcountrieswantmorerobots. 2WhichofthefollowingbestexplainspositunderlinedinParagraph3? A.Want. B.Remove. C.Assume. D.Obey. 3Howmuchwilltherobotpopulationgrowifthehumanpopulationgrowthdecreasesby3%? A.1%. B.2%. C.3%. D.6%. 4Whydoesageingcreatedemandforrobots? A.Becauseretiredpeoplehavelowerwages. B.Becauserobotsaresubstitutesforretiredworker. C.Becauserobotsareunprofitableinyoungcountries. D.Becausetheretiredneedthesamerobotstheyusedbefore.
已知一组数据1323.835.2ab的线性回归方程为则b﹣1.04a＝．
WhenIwasachildIoftendreamedofthetimewhenIcouldleavehomeandescapetothecity.Welivedonafarmandinthewinterespeciallywewerequitecutofffromtheoutsideworld.AssoonasIleftschoolIpackedmybagsandmovedtothecapital.HoweverIsoondiscoveredthatcitylifehasitsproblemstoo. Onebigdisadvantageismoney﹣﹣﹣itcostssomuchtogooutnottomentionbasicslikefoodandhousing.Anotherdisadvantageispollution.Isufferfromasthma哮喘andattimestheairissobadthatIamafraidtogooutside.Thenthereistheproblemoftravellinground.AlthoughIhaveacarIseldomuseitbecauseofthetrafficjams.Onechoiceistogobybicyclebutthatcanbequitedangerous. Ofcoursethereareadvantages.Firstthereissomuchtodointhecitywhateveryourtastesincultureorentertainment.Besidestherearewonderfuljobsandgreaterchancesofmovingtoamoreimportantjoborposition.Finallyifyoulikeshoppingthevarietyofgoodsisverysurprising﹣﹣﹣andwhatismoreshopsareoftenonlyashortwalkaway. Islifebettertheninthecity?Perhapsitiswhenyouareinyourteens十几岁ortwenties.Howeverasyougetolderandespeciallyifyouhavesmallchildrenthepeaceofthecountrysidemayseempreferable.Icertainlyhopetomovebacktheresoon. 1Whatwasthewriteralwaysthinkingaboutwhenhewasachild? A.Stayingonthefarm B.Movingtothecountryside C.Leavinghomeforthecity D.Runningawayfromtheschool 2Whichofthefollowingistrueaboutthewriter? A.Heisveryoldnow. B.Heisingoodhealth. C.Heprefersdrivingacar. D.Helivesinthecitynow. 3Inthepassagethewritertriesto. A.expresshisopinionsaboutwayoflife B.describehislifeinthecountryside C.showaninterestintheoutsideworld D.persuadethereadertoliveinthecity 4Howisthepassagemainlydeveloped? A.Byinferring B.Bycomparing C.Bylistingexamples D.Bygivingexplanations
YearsagoIlivedinabuildinginalargecity.Thebuildingnextdoorwasonlyafewfeetawayfrommine.TherewasawomanwholivedtherewhomIhadnevermetyetIcouldseeherseatedbyherwindoweachafternoonsewingorreading. AfterseveralmonthshadgonebyIbegantonoticethatherwindowwasdirty.Everythingwasunclearthroughthedirtywindow.IwouldsaytomyselfIwonderwhythatwomandoesn'twashherwindow.Itreallylooksterrible. OnebrightmorningIdecidedtocleanmyflatincludingwashingthewindowontheinside. LateintheafternoonwhenIfinishedthecleaningIsatdownbythewindowwithacupofcoffeeforarest.Whatasurprise!Acrossthewaythewomansittingbyherwindowwasclearlyvisible.Herwindowwasclean! Thenitdawnedonme.Ihadbeencriticizing批评herdirtywindowbutallthetimeIwaswatchinghersthroughmyowndirtywindow. Thatwasquiteanimportantlessonforme.HowoftenhadIlookedatandcriticizedothersthroughthedirtywindowofmyheartthroughmyownshortcomings? 1Thewritercouldn'tseeeverythingclearlythroughthewindowbecause. A.thewoman'swindowwasdirty B.thewriter'swindowwasdirty C.thewomanlivednearby D.thewriterwasnear﹣sighted 2Thewriterwassurprisedthat. A.thewomanwassittingbyherwindow B.thewoman'swindowwasclean C.thewomandidcleaningintheafternoon D.thewoman'swindowwasstillterrible 3TheunderlinedsentenceItdawnedonmeprobablymeans. A.Ibegantounderstandit B.itcheeredmeup C.Iknewitgrewlight D.itbegantogetdark 4Fromthepassagewecanlearn. A.oneshouldn'tcriticizeothersveryoften B.oneshouldoftenmakehiswindowsclean C.onemustjudgehimselfbeforehejudgesothers D.onemustlookatothersthroughhisdirtywindows
已知函数fx＝|2x﹣3|+|x+1|． Ⅰ求不等式fx≤5 Ⅱ若不等式fx≥|2x+a|的解集包含[01]求实数a的取值范围..
已知二项式的展开式中各项的二项式系数和为512日展开式中的常数项为则a＝
1 Todaykidshavemoreworriesandfacemorepressuresthaneverbefore.Hereareafewtipstohelpyourchildfocusonanddowellinschool. ●Createapersonalschedule Recordingeverythingthatmustbedoneonacalendarortodolistwillhelphimtokeeptrackofimportantdatesanddeadlines.Ifhekeepsitinavisibleplacehewillhavenoproblemacknowledgingupcomingeventsandwillbebetterabletoplanhowandwheretospendhistime. ●Watchtheclock 2Ialsorecommendsettinghisclockorwatchfiveminutesaheadsinceit'salwayseasytorunlate.Whenitcomestosomethinglikecatchingabusjustfiveminutescanmakeasignificantdifference. ●Focus Heshouldtrainhimselftobeabletoconcentratealoneononespecifictask.Thisismucheasierinanoise﹣freeenvironment.NoTVorradioshouldbeontodistracthim. ●3 Lackofsleepisproventoharmusphysically.Themoresleepwegetthemorealertweare.Wethushavemoreenergytohandlelife'sdailytasks.Theaverageadultneedsatleastsixhoursofsleepanightandtheaveragechildneedsatleasteight. ●Stayinshape Throughspendingtimeoutdoorsorplayingsportswithfriendshecanblowoffsomesteamsotospeakaswellasre﹣energize.4 ●Talkthroughyourproblems Beabletosharehisconcernswithyou.5Ifyoumakeitclearthatyouunderstandhimandarewillingtohelpnotonlywillyoucontributetohisemotionalhealthbutyou'llhelpbuildanopenandhonestrelationshipaswell. A.Sharingfeelingsoftenmakesthemeasiertodealwith. B.Helpyourchildworkbettertorealizehisaim. C.Settinganalarmforthemorningisamust. D.Getenoughsleep. E.Helpyourchilddobetterinschool. F.Encourageyourchildtobepositive. G.Encouragehimtogetoutside.
李华因在学校使用手机被学校处分他感到很困惑写信向你求助.请根据以下提示给李华回信.开头已给出不计入字数.所给要点必须写到自己可以适当补充相关细节.字数100左右. 手机的优点与家人朋友联系方便 带手机上学的问题影响教学铃声打扰师生花大量时间打手机有害学习和健康 打扰disturb Yourletterreachedmeyesterday.Yousaidinyourletterthat
已知b＝ln3c＝log0.31.5则abc的大小关系为
某地为了调查市民对“一带一路”倡议的了解程度随机选取了100名年龄在20岁至60岁的市民进行问卷调查并通过问卷的分数把市民划分为了解“一带一路”倡议与不了解“一带一路”倡议两类．得到下表 Ⅰ完成下面的2×2列联表并判断是否有90%的把握认为以40岁为分界点对“一带一路”倡议的了解 有差异结果精确到0.001 Ⅱ以频率估计概率若在该地选出4名市民年龄在20岁至60岁记4名市民中了解“一带一路” 倡议的人数为X求随机变量X的分布列数学期望和方差． 附 其中n＝a+b+c+d．
Whenmostofusgetatextmessageonourcellphonefromanunknownpersonweusuallysaysorry1number!andmoveon.ButwhenDennisWilliams2atextthatclearlywasn'tintendedforhimhedidsomething3. OnMarch19Dennisgotagrouptext4himthatacouplehedidn′tknowwereatthehospitalwaitingforthe5ofababy. Congratulations!ButIthinksomeonewasmistakenDennis6.Thebabywasbornandupdatetextswere7quicklyfromtheoverjoyedgrandmotherTeresa.Inher8shedidn′tseemtorealizedthatshewas9thebaby′sphotoswithacompletestranger.WellIdon't10youallbutIwillgettheretotakepictureswiththebabyrepliedDennisbeforeaskingwhichroomthenew11werein. Muchtothefamily'ssurpriseDennisstucktohis12!Heturnedupatthehospital13giftsforthenewmotherLindseyandherbabyboy.Lindsey′shusbandwastotally14bytheunexpectedvisit.Idon'tthinkwewouldhaverandomlyinvitedhimoverbutwe15itandthegifts. Teresa16aphotoofthechancemeetingonasocialnetworkingwebsite17bythetouchingwordsWhata18thisyoungmanwastoourfamily!Hewasso19andkindtodothis.Theposthassincegainedthe20ofsocialmediausersallovertheworldreceivingmorethan184000sharesand61500likesinjustthreedays. 1A.unlucky B.secret C.new D.wrong 2A.received B.translated C.copied D.printed 3A.reasonable B.special C.necessary D.practical 4A.convincing B.reminding C.informing D.warning 5A.wake﹣up B.recovery C.growth D.arrival 6A.responded B.interrupted C.predicted D.repeated 7A.comingin B.settingout C.passingdown D.movingaround 8A.opinion B.anxiety C.excitement D.effort 9A.comparing B.exchanging C.discussing D.sharing 10A.accept B.know C.believe D.bother 11A.parents B.doctors C.patients D.vistors 12A.dream B.promise C.agenda D.principle 13A.bearing B.collecting C.opening D.making 14A.discouraged B.relaxed C.astonished D.defeated 15A.admit B.need C.appreciate D.expect 16A.found B.selected C.developed D.posted 17A.confirmed B.simplified C.clarified D.accompanied 18A.pity B.blessing C.relief D.problem 19A.smart B.calm C.sweet D.fair 20A.sympathy B.attention C.control D.trust
Acouplehadbeenmarriedforover60years.Theysharedeverythingtalked1everythingandkeptnosecretsfromeachotherexceptthatthewomanhadaboxinadrawer2shehadcautionedherhusbandnevertoopenoraskherabout. He'dneverthoughtaboutiteversince.Oneday3womangotverysickandthedoctorsaidshewouldn'trecover.Tosortouttheiraffairsthehusbandtookdowntheboxand4bringittohiswife'sbedside.Sheagreeditwastimethatheshouldknow5wasinthebox. 6openithefoundtwosmalltablematsandasumofmoneytotaling$25000.Heaskedheraboutthecontents.Whenweweretobemarriedshesaidmygrandmatoldmethesecretofhappy7marrywasnevertoargueandIshouldjustkeepquietandmakeamat8Igotangrywithyou. Themanwasso9movethathehadtofightbacktears.Shehadonlybeenangrywithhimtwiceinallthoseyearsoflivingandloving!Honeyhesaidthatexplainsthematsbutwhataboutthemoney?Wherediditcomefrom? Ohshesaidthat'sthemoneyImadefromselling10.
假定英语课上老师要求同桌之间交换修改作文请你修改你同桌写的以下作文.文中共有10处语言错误每句中最多有两处.每处错误仅涉及一个单词的增加删除或修改. 增加在缺词处加一个漏字符号Λ并在其下面写出该加的次. 删除把多余的用斜线\划掉. 修改在错的词下划一横线并在该词下面写出修改后的词. 注意1.每处错误及其修改均仅限一词 2.只允许修改10处多者从第l1处起不计分. NextweekourschoolwillholdaChinesespeechcontestintendingforforeigners.ThecontestwhichtopicistheMostBeautifulFamilywilltakeplaceinourschoolhall.Itwillstartat9am.onamorningofJune9th.Webelieveinternationalstudentsinourschoolhadalottosharebecausefamilymattersmuchwhereverwearefrom.Howeverwebelieveitcanarousestudent'sawarenessoffamily. Whendeliveringthespeechcontestantsshouldspeakclearandloudlywithoutreferringtheirnotes.Alsotheyshouldkeepupinmindthattheyhaveonlyfiveminutesforit.Hopeeverythinggosmoothly.Lookingforwardtothearrivalofthatday.
JacobandWilhelmGrimmweretwoyoungmenfromGermanywholovedagoodstory.Asuniversitystudentstheybecameinterestedinfolktales﹣traditionalstoriesthatpeoplememorizedandtoldagainandagain.TheybegantocollecttraditionalfolktalesfromstorytellersalloverGermany.ManyweresimilartostoriestoldinFranceItalyJapanandothercountries.Between1812and1814thebrotherspublishedtwobooksinGerman.TheseincludedstorieslikeHanselandGretelandLittleRedRidingHood. DespitethefactthatJacobandWilhelmGrimmareoftenassociatedwithSnowWhiteandRapunzelthebrothersdidn'tactuallywriteanyofthosestories.InfactthestoriesexistedlongbeforethetwomenwereborninGermanyinthemid1780s.Thefairytalesinfactwerepartofarichoraltradition﹣passeddownfromgenerationtogenerationoftenbywomenseekingtopassthetimeduringhouseholdchores.In1812JacobandWilhelmpublishedthestoriesaspartofacollectiontitledNurseryandHouseholdTalesorwhatisnowknownasGrimm'sFairyTales. TheGrimmbrothers'taleswereabouttraditionallifeandbeliefs.ForexampleforestsarecommoninGermanyandthisimageoftenappearsintheGrimms'stories.Inthepastmanypeoplebelievedforestsweredangerousplaces.IntheGrimms'storiesaforestisthehomeofevilwitchestalkinganimalsandothermagicalbeings. Althoughmostpeopletodaythinkofthesestoriesasfairytalesforchildrenthebrothersfirstwrotethemforadults.Manyoftheirearlytalesweredarkandalittlescary.Laterthebrotherschangedthetextofsomeoftheoriginalstories.Theysoftenedmanyofthetalesandaddeddrawings.Thismadethemmoreappropriate合适的forchildren.Liketheearlytalesthougheachstorystillhasamoralworkhardbegoodandlistentoyourparents. Actuallyuniversity﹣trainedphilologists语言学者andlibrariansJacobandWilhelmGrimmpublishedmorethanfairytales.Theywrotebooksaboutmythologyandpublishedscholarlyworksonlinguisticsandmedievalstudies. 1Whatisthemainpurposeofthereading? A.TocomparetheGrimms'storiestomodernchildren'sstores. B.ToexplainwhystorytellingisimportantinGermany. C.ToexaminetwooftheGrimms'fairytales. D.TogiveinformationabouttheGrimmbrothersandtheirstories. 2WhichofthesestatementsistrueabouttheGrimmbrothers? A.Theyinventedthefairytalesintheirbooks. B.Theywrotetheirbooksindifferentlanguages. C.Theybecameinterestedinfolktalesasstudents. D.Theytraveledtomanycountriestocollectstories. 3WhichofthefollowingbestexplainsamoralunderlinedinParagraph4? A.interest B.text C.story D.message 4WhatdoweknowabouttheGrimms'stories? A.Thelaterstorieshadmoralsliketheearlyones. B.Theearlystorieswerewrittenforchildren. C.Theearlystorieshadalotofdrawings. D.ThelaterstoriesreflectedGermanlifebuttheearlyonesdidn't.
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