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在平面直角坐标系中，以坐标原点O为极点，x轴的正半轴为极轴建立极坐标系．已知直线l的参数方程为（t为参数），曲线C的极坐标方程为ρ=4cosθ； （Ⅰ）求直线l的直角坐标方程和曲线C的直角坐标方程...
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高三下学期数学《》真题及答案
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以直角坐标系的O.为极点x轴正半轴为极轴且在两坐标系中取相同的单位长度平面内的点P.的极坐标为34则
第一象限
第二象限
第三象限
第四象限
若曲线的极坐标方程为ρ＝2sinθ＋4cosθ以极点为原点极轴为x轴正半轴建立直角坐标系则该曲线的直
在直角坐标系xOy中以原点O.为极点x轴的正半轴为极轴建立极坐标系.曲线C.1的参数方程为t为参数曲
在极坐标系中曲线C.1和C.2的方程分别为和＝1以极点为平面直角坐标系的原点极轴为x轴的正半轴建立平
在直角坐标系中以坐标原点为极点x轴正半轴为极轴建立极坐标系曲线α为参数与曲线ρ2－2ρcosθ＝0的
在直角坐标系xOy中以O.为极点x轴正半轴为极轴建立极坐标系曲线C.的极坐标方程为曲线C.的直角坐标
曲线C.的直角坐标方程为x2＋y2－2x＝0以原点为极点x轴的正半轴为极轴建立极坐标系则曲线C.的极
设曲线C.的参数方程为t为参数若以直角坐标系的原点为极点x轴的正半轴为极轴建立极坐标系则曲线C.的极
在极坐标系中直线l的极坐标方程为θ=ρ∈R以极点为原点极轴为x轴的正半轴建立平面直角坐标系曲线C.的
理在直角坐标系中圆C的参数方程是θ为参数以原点为极点以x轴正半轴为极轴建立极坐标系则圆C的圆心极坐标
在平面直角坐标系中以原点O.为极点x轴的正半轴为极轴建立极坐标系.已知圆ρ＝所截得的弦长为2求θ0的
已知平面直角坐标内两点A02B−40AB的中点是M以原点为极点x轴正半轴为极轴建立极坐标系则M的极坐
在直角坐标系xOy中以原点O.为极点x轴的正半轴为极轴建立坐标系.已知射线θ＝与曲线t为参数相交于A
已知曲线C.的极坐标方程为ρ＝2cosθ以极点为原点极轴为x轴的正半轴建立直角坐标系则曲线C.的参数
在平面直角坐标系xOy中直线l的参数方程为t为参数P.Q.分别为直线l与x轴y轴的交点线段PQ的中点
已知曲线C的极坐标方程为4ρ2cos2θ+9ρ2sin2θ=36以极点为平面直角坐标系的原点极轴为x
在直角坐标系xOy中以原点O.为极点x轴的正半轴为极轴建立极坐标系.若极坐标方程为ρcosθ＝4的直
在直角坐标系xOy中以原点O.为极点x轴的正半轴为极轴建立极坐标系.已知射线θ＝与曲线t为参数相交于
在平面直角坐标系xoy中已知曲线C.的参数方程为α为参数现以O.为极点x轴的正半轴为极轴建立极坐标系
在直角坐标系xOy中以原点O.为极点x轴的正半轴为极轴建立极坐标系.曲线C.1的参数方程为t为参数曲
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MTLEDANONICECENTER*900CEDARBOULEVARD* PITTSBURGHPA15228 412561﹣4363www.mtlebanon.org WHOSkatersofallagesandabilities.Mustbe3yearsofageandpottytrained. AnyPreschoolKindergartenagechildwhohasnevertakenlessonsattheMr.LebanonIceCenterneedstobeevaluated. TheOn﹣lineregistrationfeaturedoesnotapplytoevaluationregistration. Evaluationdatesandtimesarelistedbelow. EVALUATIONSEvaluationshelptodeterminebothreadinessandclassplacement.Uponcompletionoftheevaluationitisrecommendedthatyouregisterforclasseswithanassociatelocatedintheicecenterbooth.AvarietyofdaysandtimesfortheevaluationsarealsolistedonlineandattheIceCenter. Evaluationregistrationmaybedoneinpersonorbyphoneat412﹣561﹣4363. AdditionalevaluationdatesmaybeofferedforsessionⅡ. REFUNDPOLICYRefundrequestsmustbemadeaminimumof7dayspriortoevent.Seewww.mtlebanon.orgfordetails. REGISTRATION Inperson﹣StopbytheMt.LebanonRecreationCentergroundfloorMondaythroughSaturday900a.m.900p.m.orSunday900a.m.530p.m. ByPhone﹣CalltheIceCenterat412561﹣4363toscheduleyourskatingevaluationappointment MakecheckspayabletoMt.LebanonPAvisaMasterCard&DebitCardsaccepted QLESTIONSPleasecalltheMt.LebanonIceCenterstaffat412561﹣4363 LeboALERT﹣AFREEnotificationservicephonetexte﹣mail.Intheeventofanemergencyandtoprovideyouwithupdatesaboutcancellationsandrecreationdepartmentprogramsandevents.Pleasevisitwww.mtlebanonorgandsignupforLeboALERT.AllrecreationparticipantsshouldsignupandatminimumselecttheCancellationscategory. 1What'sthepassagemanlyabout? A.Tointroduceaskatingprogram. B.Toadvertiseaskatingcenter. C.Toserveasaskatingassessmentschedule. D.Toissueafreeskatingnotification. 2Mary'smotherwantstoregisterstheevaluationforherdaughter.Whichtimeasfollowsissuitableforhertogotothecenter? A.Monday830a.m. B.Wednesday2p.m. C.Friday930p.m. D.Sunday600p.m. 3Whichofthefollowingistrueaccordingtothepassage? A.Theevaluationisintendedforallpreschoolandkindergartenchildren. B.Refundrequestscanbeacceptedwithin7daysaftertheregistration. C.ParticipantswhosignupforLeboAlertcanreceivefreenotificationabouttheevent. D.Evaluationregistrationcanbedoneinpersonbyphoneoron﹣line
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ChinesePresidentXiJinpinghaspraisedagroupofmiddleschoolstudentsfortheireffortsinsatellitedesign.Hesaidhewaspleasedwiththeircuriosityandbraveryin1scienceexploration. ThepresidentalsowishedtheteachersandstudentsinBayiSchool2happynewyear. Ximadethepraiseinaletter3writetothestudentsinBeijing'sBayiSchoolonSaturday. Asmallsatellitedesignedanddevelopedbythem4sendintospacelastWednesdayatTaiyuanSatelliteLaunchCenter5itwasdesignedtooperateinorbitfor180days. ThreemonthsagoXireturnedto6hehighschooltovisitalaboratoryandtalktoteachersandstudents7weredesigningthesmallsatellite.Thepresidentsaidhewas8extremegladtoknowthatthesatellitedesignedbythestudentswouldbelaunchedandcalledonthemtobecome9buildofthecountry.Xiwarmlyencouragedthestudents10studyscienceandcontributetothedevelopmentofChina.Hehopedthatthestudentswouldkeephungryforknowledgeanddeveloptheirnationalspirit.
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IntheshorttimeSteveandZachhadbeeninsidetheirtentpackingtheirtoolswind-blownflamehadskippedfromthetopofonetreetoanother.Thelongdrysummerhadturnedtheforestintoatinderbox. Let'sgo!Wecanmakeitbacktotheriverwecrossedtoday!StevekeptBradyontheleadandtheirheadsdownagainstthefire-wind.ButBradybarkedasharpwarning.Aheadofthemlayathickcurtainofsmokeacrossthetrack.Theywouldnevermakeitthroughthat.ThedogwaspullingathisleadtryingtodrawthemawayfromthesmokeandyetStevewasuneasy.Itseemedtohimthattheyweremovingawayfromtheriver. SuddenlyZachcried.Zach!Steveshouted.AreyouOK?Whereareyou?ThenBradypulledStevedownasharpslope坡.AtitsbaseZachwasrubbinghisankle. AsStevehelpedhisfriendtohisfeetBradyliftedhisheadandsnuffed嗅thesmoke-ladenwind.Nextmomentthedogboundedawayanddisappeared.Theboysshoutedforhimbuthedidn'tcomeback.Stevecouldn'tblameBradyforpanicking.Hehimselfwantedtoruneventhoughhedidn'thaveacluewhichway. SteveandZachhadn'tgonefarwhentherewasafamiliarbarkandBradycameboundingstoppeddirectlyinfrontofSteveandhithimwithhisheadpushinghimbacktowardtheslopethey'djustclimbed.ButStevedidn'tgetit.ThenBradygrabbedtheboy'sjeansandstartedpulling.ThemessagewasclearbutStevehesitated.OfcourseherememberedBradysavinghisuncle'slifewhenthedogwasmuchyounger.Washestillsharpenoughtogetthemthroughthis? Nearbyapinewentupinawhooshofsmoke.Bradypulledagainurgently.OKbigguyStevegritted咬紧牙关.Bradyledthembackdowntheslopeandintothetrees.Notfarfromthemfirewastouchingunderbrush.Severaltimesthebigdogstopped.Oftenhechangeddirections.StevewassotiredthathejustwantedtorestbutBradywouldn'thaveit.Thedogbulliedbothboystogoon.Howlongthey'dwalkedStevehadnoidea.Hewasalmostnumbwhenheheardit-thewonderfulsoundofrushingwater! 1WhathappenedtoSteveandZachatfirst? A.Theygotinjured. B.Theylosttheirdog. C.Theyweretrapped. D.Theybecameseparated. 2Bradyranawayto. A.seekhelp B.findawayout C.rescueZach D.escapeforlife 3HowdidStevefeelafterBradypulledhisjeans? A.Uneasy. B.Impatient. C.Numb. D.Uncertain. 4Thepassagebasicallydescribes. A.anadventure B.anexploration C.anescapegame D.atrainingprogram
Iwillneverforgetonesummerinmychildhood.Whilewalkingintheattic阁楼Isteppedonsomethingand1downwithmyhandlandingonafloorboardthatpoppedupandalmosthitmeinthehead.WhenI2andlookedinsidetheopenspaceIcouldnotbelievemyeyesTherewasgoldinthere!I3ahandfulofshininggoldcubesrantothebottomstairand4MamaIfoundgolduphereunderthefloor! BackupthestairsIdashed5mybotheralmostknockedmebackdownastheyranrightbyme.WhenMamaopenedthedoorand6herheadinshe7saidHoneythat'sinsulation隔热材料.Nowputitallback. Ifeltreallydisappointed.IhadthoughtImadeareal8. WhenI9insidetoputthefakegoldbackmyhandtouchedwhatfeltlikeabook. Ipulleditout.ItwasoldandsmallBartlett'sFamiliarQuotationswhichI'dneverheardof. And10IwasboredIdecidedtoseewhatwasinsidethislittlebook.Tomy11itwasabookofpassagesphrasesandproverbsandIcouldtellthatthiswasgoingtobe12. SoIspentquitemuchtimeonitandfound13inthesepages.AsIdidn'tknowhowtoexpressthingsclearly.Ioften14totalkaboutthemThisbookhelpedme15thatIdidn'tneedtofeelashamedor16becauseotherpopehadsimilarexperience. WhenIwenttocollegeBartlett'scamewithme.OvertheyearsI'vekeptmyoriginal17whichtothisdayIoften18Althoughitwasa19tofindthebookitliberatedmeinaway.Ithelpedmeseemorethanmyyoungmindandheartwereabletounderstand. Thebookdiscoveredunderthosefloorboardswas20gold. 1A.slowed B.calmed C.looked D.fell 2A.bentover B.showedup C.laydown D.brokein 3A.stole B.produced C.seized D.hid 4A.yelled B.sighted C.admitted D.complained 5A.or B.so C.but D.for 6A.nodded B.stuck C.lowered D.lifted 7A.simply B.thoughtfully C.honestly D.angrily 8A.difference B.choice C.mistake D.discovery 9A.sat B.slid C.reached D.walked 10A.until B.nowthat C.unless D.sothat 11A.surprise B.regret C.relief D.disappointment 12A.absurd B.controversial C.boring D.interesting 13A.sympathy B.comfort C.honor D.doubt 14A.tended B.offered C.managed D.hesitated 15A.expect B.remember C.realize D.imagine 16A.embarrassed B.satisfied C.astonished D.tired 17A.mind B.copy C.plan D.file 18A.putaway B.showoff C.referto D.pickup 19A.dilemma B.disaster C.pity D.coincidence 20A.still B.indeed C.normally D.hopefully
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EveryyeararoundValentine'sDaymenbegintoworryaboutwhat1presenttobuyandwomen2fillwithhopeandexpectation.Ortheotherwayaround.InChinamorecouplesgetmarriedonthatveryday3addromancetotheirpromises.Butformanyloveisneitherthematter-of-coursechoice4thepreferredone.Moreyoungworkingurbanresidentsaredelayingorevenchoosingnotto5activeseektheirpartnersdespitethesocialpressurefromtheoldergenerationstodoso. OvertheyearsChina'sdivorceratehasexceeded超过thatofmarriage.AccordingtothestatisticsfromtheMinistryofCivilAffairs10millioncouplesregisteredformarriagein2017fellby7%6comparewiththesameperiodlastyearwhile43.7millioncouplesdivorced5.2%morethanthesameperiodlastyear. Thereisalsoagrowingtrendtowardspeoplemarryinglatersince2013thenumberofcouplesaged25to29hasbeengreaterthan7ofyoungercouples.Inthe8latesurveyonprofessionalattitudestowardsloveandmarriagemorethanhalfoftheinvestigatedinYangzhou9second-levelcityontheEastcoastweresatisfied10theirmarriageafter35.
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图甲为一列沿x轴传播的简谐横波在某时刻的波形图Q为平衡位置为x1＝10cm的质点P为平衡位置为x2＝17.5cm的质点．图乙为Q质点从该时刻起的振动图象．①判断波的传播方向②从该时刻起在哪些时刻质点Q会出现在波峰③从该时刻起P点第二次回到平衡位置通过的路程结果保留3位有效数字．
博物馆疏于管理展品积灰门厅冷清急需改善.whose
PeopleYou'veNeverHeardofWhoChangedtheWorld Itisafactthatmostpeoplelivetheirlivesunremarkedbyhistory.Whetherbydesignorbyaccidenttherearesomepioneerswhoseachievementschangedthecourseofhistorybutwhosenamesareunknowntous. JamesHarrison JamesHarrisonhassavedthelivesofovertwomillionpeoplebydonatinghisblood1173timesaGuinnessworldrecord.Hisbloodproducesarareantibody抗体whichcurestheotherwisedeadlyRhesusdiseaseinunbornchildren.Ithasalsobeenusedinthedevelopmentofamedicineanti-DwhichwillcuretheRhesusdiseaseinchildrenforever. LewisLatimer AfterhelpingAlexanderGrahamBellobtainhispatentforthetelephoneLewisLatimerpatentedacarbonfilament碳灯丝whichallowedlightbulbstoburnforhoursbeforeburningoutmuchmoreusefulthanthatinventedbyThomasEdison.Latimerwentontoinventmanyotherusefuldevicesincludingadevicewhichcooledandcleanedpatients'roomsinhospitals. MauriceHilleman Notallachievementsrequirebraveryandself-sacrifice.TakeMauriceHillemanforexample.Hefoundanotherwaytochangetheworld.Hedevelopedthemumpsvaccine疫苗afterhisdaughtergottheillness.Andhedidn'tstopthere.Intotalhehassingle-handedlydevelopedover40vaccinesincludingeightcommonlygiventochildren.Hisworkhassavedmillionsoflivesandpreventedseriousconsequencesduetothediseases. NilsBohlin In1959NilsBohlinpatentedarevolutionarydesignthathassavedmillionsoflives-thethree-pointsafetybelt.Aftertheinitialresistancefromdriverswhohatedbeingtoldwhattodoandevenfortheirowngoodthethree-pointbelthasbecomeastandardfeatureinnewcarsaroundtheworld. 1Whosepatentallowedlightbulbstoburnforhoursbeforeburningout? A.AlexanderGrahamBell. B.LewisLatimer. C.ThomasEdison. D.NilsBohlin. 2What'sthesimilaritybetweenJamesHarrisonandMauriceHilleman? A.Theybothhadspiritsofbraveryandself-sacrifice. B.Theircontributionssavedthelivesofmanychildren. C.Theydevotedthemselvestoworkbecauseoffamilymembers. D.TheybothsetaGuinnessworldrecord. 3Whatwasdrivers'initialattitudetothethree-pointseatbelt? A.Theyrefusedtouseit. B.Theyweresatisfiedwithit. C.Theyweresurprisedatit. D.Theygotexcitedaboutit.
Helicopterparentingdescribesastyleofraisingchildrenwhereparentsareoverprotectiveanddotoomuch.Itdescribesparentswhowatchovertheirkidsathomeandontheplaygroundlikeahelicopter.Todaymoderntechnologyallowsthesehelicopterparentstowatchoverfromevenfaraway.1 JulieLythcottwroteabooktitledBreakFreeoftheOverparentingTrapandPrepareYourKidsforSuccess.Inherbook.shegivesreadersacloserlookatthisparentingstyle.2 JulieLythcottsayssheexperiencedtheeffectsofhelicopterparentingfirsthandwhensheworkedasdeanoffirstyearstudents.3Butmanywereunabletotakecareofthemselves.Heywereturningtoparentsconstantlyforguidanceforproblemsolvingtohavethemmakethechoiceaboutsomething. Sowhatcanparentsdoiftheywanttobreaktheover-parentinghelicoptercycle?4 ◆Stopsayingwewhenyoumeanyoursonoryourdaughter.Alltoooftenaparentwouldsayweareonthetravelsoccerteam.Wellnoyoursonisoryourdaughteris. ◆Stoparguingwithalloftheadultsinourkids?lives.Youneedtoteachyourkidstoadvocateforthemselves. ◆Stopdoingyourkids'homework. ◆5Teachthemtocrossthestreetmakeamealandremembertoputtheirownitemsintheirbackpackswhichbecomesabriefcaseoneday. Whenkidshavealltheskillstotakecareofthemselvestheywillbepreparedforadulthood. A.Fourwaysareofferedtostopwatchingoveryourchildren. B.Shealsoexplainswhyparentsshouldstopit. C.It'sagoodideatoencourageyourkidtodothethingshecanbyhimself. D.Theycangivetheirchildrendirectionsatanymomentfromanywhere. E.Buildyourkids'skills. F.Thefreshmenwereverysmartandaccomplishedonpaper. G.Yourkidiseagerformorefreedombutshouldyougiveittohim?
Areyoutryingtofindwaystobemoreefficientatyourjob?Ifsopleasefollowthesehabitsofnaturallyproductivepeople. Theytakebreaks.1Studiesshowthatprolongedtasksthatrequirehighlevelsoffocusenergyandattentioncancauseyoutobecomelessproductiveandfocusedovertime.Takebriefmentalbreaks.Settingasidealittletimehereandtheretoreleaseyourfocuscansignificantlyhelpmaintainitforlongerperiodsoftime. 2Settledownsupermenandwomen.Whileit'sfinetoprideyourselfonyourabilitiestomultitaskit'sinyourbestinterestandyouremployer'sifyousticktooneto-doatatime.Somewherealongthelinesourculturehasembracedandpromotedthisideathatthemorewecandoatoncethebetter.3Infactthemorewemulti-taskthelessefficientandproductivewebecomeinallthetaskswearetryingtoaccomplish. Theyhaveafullnight'ssleep.Inschoolyoumayhavefoundthattoomanystudentsstayuplatetofinishapaperorstudyforanexambutdespiteyourbesteffortsresearchshowsthisisnotthewaytodobusiness.4Actuallystudieshavelinkedinsufficientsleeptodecreasedlevelsofproductivityunsatisfactoryworkperformanceandpoorersafetyoutcomes. 5Youknowthecountlessbenefitsofexercise.Italsoseriouslyimprovesyourmoodbyreleasingsomethingtorelievestressandincreaseyourbrainsproductivity.Even30-minuteburstsofmoderate-to-highphysicalactivityjustthreetofourtimesadaycangoalongwayinhelpingyouaccomplishyourpersonalandprofessionalgoals. A.Theyvaluefitness. B.PressingpauseIsImportant. C.Theyprefertodomoreeveryday. D.Howeverresearchshowstheopposite. E.Theydon'ttrytodoeverythingatonce. F.Enoughsleepmakesgreatcontributiontoefficientwork. G.Poorsleeporlackofsleepcarriessomeprettynegativerewards.
已知点P是边长为2的正方形ABCD所在平面内一点若则的最大值是
OKsoit'snotarealwar-buttheU.S.andChinaareatthebeginningofatradewarthankstoPresidentTrump'spolicy.TheChinesegovernmentraised34billiondollarsinnewdutiesongoodsexportedfromtheU.S.lastweekinreplytoPresidentTrump'sunwisetariffs关税of34billiondollarsonChinesegoods. Farmandseafood-producingstatesaregoingtobehithardestbyChina'snewtariffsonU.S.goods.StateswherecarsaremadeandshippedtoChinaareonthehookaswell. Intermsofvaluesome38percentofproductsonthetarifflistarerelatedtoagricultureincludingsoybeanssorghumtobaccoandmeat.That'snothinglikegoodnewsforfarm-beltstatesprimarilyintheMidwestlikeIowa. AwiderangeofseafoodisonChina'starifflist.ThatcouldhurtfisheryworkersinAlaskaandlobsterharvestersinMaine.AlaskaforexampleexportednearlyIbilliondollarsworthofseafoodtoChina.ChinaisamajormarketforAlaskaseafoodsaidAlexaTonkovichExecutiveDirectoroftheAlaskaSeafoodMarketingInstitute.Theseafoodindustrydirectlyemploysnearly60000workersinAlaskaeachyearanddirectlyemploysmoreworkersthananyotherprivateindustry. AndautomakingstatesparticularlyintheSoutharealsoatrisk.Some24percentofproductsonthelist-intermsofvalue-arecarstrucksandothervehicles.Michiganaloneexported$1.7billionworthofmotorvehiclesandvehiclepartstoChinain2017.OtherstatesbeingaffectedincludeSouthCarolinawhereBMWmakesSUVsforboththeU.S.andexportersandAlabamahometoMercedes-BenzToyotaHondaandHyundaifactories. Thisroundoftariffssparessomeindustrieslikecommercialaircraft.WashingtonStatewhichishometoBoeingcouldbreatheasighofrelief.Italsoforthemomentskipstariffsonchemicalproducts. AlexaTonkovichhaswarnedtheU.S.governmentthatthetradewarcouldriskemploymentreduce industryprofitsandcausethehigherpricesforconsumersintheU.S.! 1Whatdoestheunderlinedphraseonthehookmean? A.Delightedintheirluck. B.Lostindeepthought. C.Caughtinadifficultsituation. D.Stuckintrafficjams. 2Whichstatewillbehurttheleastonthisroundoftariffs? A.Washington. B.Iowa. C.Maine. D.Michigan. 3WhatisAlexaTonkovich'sattitudetowardsthetradewar? A.Approving. B.Sympathetic. C.Objective. D.Opposed. 4Whichofthefollowingshowsthedevelopmentofideasinthetext? A.I-P1-Spl-Sp2-P2-Sp-C B.I-PI-Sp-P2-Spl-Sp2-C C.I-P1-P2-Spl-Sp2-Sp3-C D.I-PI-Spl-Sp2-Sp3-P2-C IintroductionPPointSpSub-point次要点CConclusion
假定你是李华你的英国朋友Peter听说现在在中国人工智能已经进入人们的日常生活包括旅游业.他来信询问你十一假期是否有这方面的体验请给他回信内容包括 1.门票无现金手机支付 2.脸部识别人景区 3.邀请他来体验. 注意 1.词数100左右 2.可以适当增加细节以使行文连贯 3.开头和结尾已给出不计入总词数. 参考词汇人工智能artificialintelligence脸部识别facerecognition DearPeter. I'mhappytohearfromyou. Yourstruly LiHua
某三棱锥的三视图如图所示则该三棱锥的体积为
Classifyingthingsiscriticalforourdailylives.Forexamplewehavetodetectspammail垃圾邮件falsepoliticalnews.WhenweuseAIsuchtasksarebasedonclassificationtechnologyinmachineearning-havingthecomputerlearnusingtheboundaryseparatingpositiveandnegativedata.Forexamplepositivedatawouldbephotosincludingahappyfaceandnegativedataphotosthatincludeasadface.Onceaclassificationboundaryislearnedthecomputercandeterminewhetheracertaindataispositiveornegative. Howeverthedifficultywithhistechnologyisthatitrequiresbothpositiveandnegativedataforthelearningprocessandnegativedataarenotavailableinmanycases.Forinstancewhenaretailer零售商istryingtopredictwhowillmakeapurchasetheycaneasilyfinddataoncustomerswhohavepurchasedfromthempositivedatabutitisbasicallyimpossibletoobtaindataoncustomerswhohaveneverpurchasedfromthemnegativedatasincetheydonothaveaccesstotheircompetitors'data. AccordingtolendauthorTakashiIshidafromRIKENAIPPreviousclassificationmethodscouldnotcopewiththesituationwherenegativedatawerenotavailablebutwehavemadeitpossibleforcomputerstolearnwithonlypositivedataaslongaswehaveaconfidencescoreforourpositivedataconstructedfrominformationsuchasbuyingintentionortheactiverateofappusers.Usingournewmethodwecanletcomputerslearnaclassifieronlyfrompositivedataequippedwithconfidence. AccordingtoIshida.Thisdiscoverycouldexpandtherangeofapplicationswhereclassificationtechnologycanbeused.Eveninfieldswheremachinelearninghasbeenactivelyusedourclassificationtechnologycouldbeusedinnewsituationswhereonlypositivedatacanbegatheredduetodataregulationorbusinessconstraints限制.Inthenearfuturewehopetoputourtechnologytouseinvariousresearchfieldssuchasnaturallanguageprocessingcomputervisionroboticsandbioinformatics. 1Howcanthecomputerdistinguishthepositivedatafromthenegativedata? A.Bylearningtheclassificationboundary. B.Byupdatingthedatacollectedregularly. C.Byseparatinghappyfacesandsadones. D.Byintroducingclassificationtechnology. 2WhyistheexamplementionedinParagraph2? A.Toprovehowimportantthepositivedataare B.Toconfirmthatdataoncustomersarecomplete C.Toarguethatretailersgettheircompetitors'data D.Toexplainwhynegativedataarehardtoacquire. 3WhatdotheunderlinedwordsnewmethodinParagraph3referto? A.Analyzingbuyingintention B.Buildingaconfidencescore C.Assessingtheactiverateofappusers D.Equippingthecomputerwithconfidence. 4Whatcanbeasuitabletitleforthetext? A.TheHistoryofClassificationTechnology B.SmarterAlMachineLearningwithoutNegativeData C.BiggerDataComputersAssistingLanguageProcessing D.TheComparisonbetweenPositiveDataandNegativeData
DuringmysecondyearinhighschoolIgotsickandmissedafewdays.WhenI1Iwasgreetedwithtwoessaysduethreedaysofmathandhistoryhomeworkplusseveraltests.2IwenthomefromschoolthatdayexhaustedIhadtostayupreallylatetofinishthemall. ThenextdayatschoolIgotarudeawakeningI'dtotallyforgottentoprepareforthe3onRomeoandJulietwhichI'dtake4mylunchhour!WorsestillIhad5thein-classdiscussionandallthenotes.WhenlunchcameIwenttotheEnglishroomtofacemycertaindoom厄运.AllIcoulddowastryto6onthequestionsIdidn'tknow. AsitturnedoutIdidn'tknowthemajorityofthequestions.Iwasjustabouttogive7whenmypencilaccidentallyfellandbroke.StandingbytheblackboardsharpeningmypencilI8downandthereinfullviewlaytheanswersheetforthetest!Whatgoodfortune!Icankissgood-byetoallmy9offailingthetest!Myheartstartedbeatingandmybrain10Yes!Readovertheanswers-quickly!ThiswasquicklyfollowedbyanothervoiceNo!You'llgetcaught!MymindturningbackandforthYes!No!Yes!No!…Thiswentonfortenofthe11secondsinmyentirelife. FinallyIdecidedtofinishthetestonmyownwithout12!Iwassatisfiedwithmydecisionbutpretty13Ihadfailedthetest. ThenextdaywhenIwalkedintotheEnglishroommygreatjoyofhavingbeenan14soulchangedintoawaveofdoomasIsawmytestpaperlyingfacedownonmydesk.Iknewwhatawaitedme.IstaredatitafewsecondsbeforeIgotupthe15toturnitover. Youcanonlyimaginemy16whenIlearnedthatIhadpassedthetest!Ihaveneverinmywholelifebeensohappytoseemy17aC-. Mymomsaysthevictoriesthat18themostcouragearewonwithin.NowIknow19whatshemeans.Nownotonlycanmyconscience良心resteasybutIdon'thavetoworryaboutgettingcaughtandmeetingasad20likeRomeoandJuliet. 1A.arrived B.returned C.appeared D.finished 2A.If B.Because C.Until D.Although 3A.lecture B.essay C.play D.test 4A.by B.upon C.over D.toward 5A.missed B.carried C.lost D.dropped 6A.depend B.agree C.guess D.improve 7A.in B.off C.out D.away 8A.wrote B.settled C.calmed D.looked 9A.boredom B.worries C.loneliness D.tiredness 10A.whispered B.warned C.persuaded D.chanted 11A.coldest B.saddest C.longest D.fastest 12A.suffering B.checking C.cheating D.thinking 13A.certain B.regretful C.annoyed D.relieved 14A.open B.honest C.optimistic D.energetic 15A.wisdom B.encouragement C.intention D.nerve 16A.anxiety B.shock C.fear D.appreciation 17A.paper B.credit C.rate D.grade 18A.take B.put C.find D.gain 19A.gradually B.exactly C.willingly D.seemingly 20A.film B.fact C.ending D.love
DirectionsReadthefollowingpassage.Summarizethemainideaandthemainpointsofthepassageinnomorethan60words.Useyourownwordsasfaraspossible.Wherearethebees?Beesareessentialtotheproductionoffoodweeat.Beesmakehoneybuttheyalsopollinatelargeareasofcropssuchasstrawberriesapplesandonions.Aboutathirdofthefoodweeatisaresultofpollinationofthebees.Unfortunatelybeeshavebeendisappearingatanalarmingrate.In2006beekeepersstartedreportingaboutsomethingcalledColonyCollapseDisasterCCD.ThemainsignofCCDisthelossofadulthoneybeesfromahive.InOctoberof2006somebeekeepersreportedthattheyhadlostbetween30and90percentoftheirhives.Thereweremanytheoriesforthedisappearanceofthebees.Butthemostconvincingonehastodowithpesticidesandlifestylesofbeestoday.Nowadaysbeekeepergetmostoftheirincomenotfromproducinghoneybutfromrentingbeestopollinateplants.Thismeansthatthelifeofthetypicalbeenowconsistsoftravellingallaroundthecountrytopollinatecropsastheseasonschange.Thatmeansalotoftravelingontruckswhichisverystressfultobees.Itisnotunusualforupto30%ofthehivetodieduringtransportduetostress.Inadditionbeesthatspendmostoftheirtimelockedupontrucksarenotexposedtowhattheyusuallyliveon.Insteadtheyliveonasweetliquidfromcornusuallypollutedwithpesticides.Theexactreasonforthedisappearanceofbeesisnotsurebutlosingbeesisverycostlytotheeconomy.Thebeepollinationservicesareworthover﹩8billionayear.Withnobeespollinationwillhavetobedonebyhandwhichwouldhaveeffectsonthequalityoffoodandincreasedfoodpriced.Wehearalotaboutbigenvironmentaldisastersalmosteveryday.Butoneofthebiggestmayjustbethelessofthattinyflyinginsect.
双曲线的离心率为．
AsimpleprojecttohelpafamilyinneedstoppedLukeMickelsoninhistracks.In2012heandhisfamilywereinspiredtobuildanddonateabunkbedonebedontopoftheotherafterlearningtherewerelocalchildrenwhosleptonthefloor.ShockedtodiscoverhowwidespreadthisneedwasinhiscommunityMickelsonfoundedSleepinHeavenlyPeaceanonprofitthatbuildsanddeliversbedstochildreninneed. BomandraisedinIdahoMickelsonnow41hadathrivingcareer.Hecoachedhiskids'sportsteamsandfishedinthenearbyriver.Butwhenhemetchildrenwhoweresleepingonthefloorhispeacefullifechangedcourse. Usingsafetyguidelinesandhisdaughter'sbunkbedasamodelMickelsonstartedbuyingwoodandsuppliestobuildbedswithhisownmoney.Herecruitedfriendsandfamilymemberstohelparoundtheholidays.Aswordspreadinterestandinvolvementfromhisandothercommunitiesflooded-alongwithMickelson'sbunkbedoutput.Thatfirstprojectwebuilt11bunkbedsinmygaragehesaid.Thenextyearwedid15.Thenitdoubledeveryyear.In2017webuilt612bunkbeds. WiththemottoNokidsleepsonthefloorinourtownthenonprofitanditsmorethan65brancheshavebuiltanddeliveredmorethan1500freebedstochildrenacrossAmerica.ButalongwiththerapidgrowthMickelsonwasfacedwithatoughchoiceadvancinghiscareerorhisnonprofit.Hechosethelatterandwentfrommakinggreatmoneytozeromoney.He'sneverlookedback.IfoundthattheneedIhaveisn'tfinancialhesaid.TheneedIhaveisseeingthejoyonkid'sfacesknowingthatIcanmakeadifference. 1WhydidMickelsonsetupSleepinHeavenlyPeace? A.Tohelpthepoorchildren B.Tomakeabigfortune C.Toinspirehiscommunity D.Togetmoredonations 2WhatdoweknowaboutLukeMickelson? A.Hehadhisownfishfarm. B.Hechangedhiscareerfromtimetotime C.Heusedtosleeponthefloorwhenhewasakid. D.Heoriginallyhadarelaxingandpleasantlife 3HowdidotherpeoplereacttoMickelson'sproject? A.Theyshowedlittleinterestinit B.Theyweresupportiveandinvolvedinit. C.Theyweredoubtfulaboutthesafetyofthebunkbed. D.Theyvolunteeredtobuybedswiththeirownmoney 4WhatisMickelson'sattitudetothenonprofit? A.Ambiguous. B.Defensive. C.Cautious. D.Positive
LastfallIhappenedtooverhearastudenttellingtheothershehaddecidednottosignupforanintroductoryphilosophycourse.Thedemandsofhismajorhesaidseriouslymeantheneededtotakepracticalcoursesandenlightenmentwouldsimplyhavetowait.Fornowemployabilitywasthemostimportant. Thestudents'conversationfitsintoalargeralarmingnarrativeabouttheroleofthehumanitiesinhighereducation.InatimeofdizzyingtechnologicalachievementandofrapidscientificinnovationscepticsofthehumanitiesmayquestiontheusefulnessofstudyingAristotletheItalianRenaissanceorChinesefiction. ActuallyIregretnotinterruptingthatstudenttoarguefortakingthatintroductoryphilosophycourse.IwouldhavestartedbyremindinghimthatformuchofAmerica'shistorycollegegraduateswerenotconsideredtrulyeducatedunlesstheyhadmasteredphilosophyliteraturepoliticaltheoryandhistory.Thekeyroleofhighereducationwastoinvitestudentsintotheconversationsaboutmatterslikewhatitmeanstobealiveandthedefinitionofjustice.Fosteringengagementwiththesesubjectsisstillanessentialpartoftheuniversity'sfunctioninsociety. Iwouldhavealsomentionedtothestudentthathewasmisinformedaboutthejobmarket.Itistruethatmanyemployersarelookingforgraduateswithspecializedtechnicalskillsbuttheyalsolookforothercapabilities.Astheworldistransformedbyartificialintelligencemachinelearningandautomationtheuniquehumanqualitiesofcreativityimaginationandmoralreasoningwillbetheultimatecoinoftherealm.Alltheseskillsaredevelopedinhumanitiescourses. FurtherIwouldhavearguedthatwhileadegreeanchoredinthesciencesisanimportantpreconditionformanyjobsitisnottheonlyroute.LooknofurtherthanthefoundersofcompaniessuchasLinkedInSlackandFlickrwhoareamongthemanytechbusinesspersonswithdegreesinthehumanitiesandwhocreditthattrainingfortheirsuccess. Contrarytothewidelyheldbeliefthathumanitiesmajorshaveahardtimegettingjobsrecentstudiesshowthatthosewithhumanitiesdegreesaresuccessfulintheworkplaceexperiencinglowratesofunemploymentandreportinghighlevelsofjobsatisfaction.Theratiobetweenaveragemedian中位数incomesforhumanitiesdegreeholdersandthosewithbusinessengineeringandhealthandmedicalsciencesdegreeshasbeenshowntonarrowoverthecourseofacareer. Thecaseforthehumanitiescanalsobeunderstoodinlesstransactionaltermsandmoreasafoundationalpreparationforalifewelllived.Ahumanitieseducationplaysavitalroleinencouragingcitizenstoleadanexaminedlife.Itfosterscriticalthinkingself-reflectionempathyandtolerancetheusefulnessofwhichonlybecomesmoreapparentasonenavigateslife'schallenges. ByallmeansstudentsshouldtakecoursestheythinkpracticalandfollowtheirinterestsbutiftheyalsomakeapointofstudyingtheliteratureoftheRenaissanceorresearchingintomodernpoetryoreventakingintroductoryphilosophywewillallbenefit. 1Whatdothestudents'conversationshow? A.Studentsfeelemploymentdifficult. B.Studentsthinkphilosophylessimportant. C.Studentsfindscientificinnovationamazing. D.Studentsconsideruniversitycoursesunsatisfying. 2WhatdoestheunderlinedpartinParagraph4probablymean? A.Highlyvalued. B.Equallyapplied. C.Strictlyassessed. D.Greatlyimproved. 3Theauthormayagreethathumanities. A.discoverstudents'artisticability B.preparestudentsforgraduation C.raiseawarenessofsocialstatus D.providegreatinsightsintolife 4Whichofthefollowingshowsthedevelopmentofideasinthepassage? A. B. C. D. IIntroductionPPointSpSub-point次要点CConclusion
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