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某文具店购进A，B两种钢笔，若购进A种钢笔2支，B种钢笔3支，共需90元；购进A种钢笔3支，B种钢笔5支，共需145元． （1）求该文具店购进A、B两种钢笔每支各多少元？ （2）经统计，B种钢笔...
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某文具店购进AB两种钢笔若购进A种钢笔2支B种钢笔3支共需90元购进A种钢笔3支B种钢笔5支共需1
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某文具店准备购进甲乙两种钢笔若购进甲种钢笔100支乙种钢笔50支需要1000元若购进甲种钢笔50支乙
某文具店购进A.B.两种钢笔若购进A.种钢笔2支B.种钢笔3支共需90元购进A.种钢笔3支B.种钢笔
某文具店购进AB两种钢笔若购进A种钢笔2支B种钢笔3支共需90元购进A种钢笔3支B种钢笔5支共需1
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开学初学校打算买630支钢笔发给学生这种钢笔的统一价是每支6元．现在2两家文具店对这种钢笔搞促销活动
某商店准备从批发市场购进甲乙两种钢笔进行销售每支甲种钢笔的销售价格为10元每支乙种钢笔的销售价格为1
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学校计划购买40支钢笔若干本笔记本笔记本数超过钢笔数甲乙两家文具店的标价都是钢笔10元/支笔记本2元
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精原细胞既可以进行有丝分裂也可以进行减数分裂下列叙述错误的是
下列探究实验不能达到实验目的是
下列有关遗传信息的传递叙述正确的是
下列关于蛋白质和核酸的叙述错误的是
三江源地区动植物种类和湿地生态系统独特是青藏高原珍稀野生动植物的重要栖息地和生物种质资源库．建立三江源自然保护区对保护好分布在该地区的生态系统生物物种及其遗传多样性具有十分重要的意义．回答下列问题 1草原上的食草动物当看到青草明显减少时部分动物个体会另觅食地这体现了生态系统的功能．该草原生态系统的食物网较为简单若外来生物入侵该地区可能会导致草原的锐减． 2为保护该生态系统科研人员经常对该地区进行调查．调查中要记录样地中每个物种的高度盖度和多度利用记名计算法统计样地内的物种． 3调查发现鼠类的啃食掘洞等活动加速了草场的退化但高原鼠兔的数量较少时不会对草原造成明显危害说明．草原上适当的“地面过火”不会破坏该生态系统反而会加速生态系统的物质循环原因是．
下列关于现代生物进化理论的叙述正确的是
下列有关生物学实验的叙述正确的是
Stampcollecting集邮iscool.Itencouragesyoutolearnaboutdifferentthings.Manystampsgiveinsight见解intoacountry'shistoryanditslandmarks.地标建筑1Youcannevergetovertheexcitementofdiscoveringandlearningnewthings.Ifyouwanttogoafterthishobbyofbeingastampcollector藏家herearesomethingstokeepinmind.Beaware留意thatstampsaren'tcollectedthewayyourgrandparentscollectedthem.Puttingtogetheraworldwidecollection世界级藏品isimpossiblethesedays.2Butthat'scoolbecauseallthatmeansyoucancollectwhateveryouwant.Figureoutwhatitems物品interestyou.3Somepeoplegetstampsfromallovertheworld.Otherssavestampsfromjustonecountry.Youmightwanttosaveaspecialtypeofstampsuchasanimalstampssportsstampsorspacestamps.Orpossiblyyoudon'ttowanttolimittoaparticulartopic特定主题.Pursue追求thishobbyaslongasitisenjoyabletoyou.4Itcanhelpyoulearnmoreaboutstampsandinteract交流互动withothercollectors.Youmayquestionthepersonthatmayhavesomecollectionsassociated相关withthesestamps.Inthissituationyoumaybeabletoswapsomeofhisstampsforaparticularstamp.Meanwhileyoucanmakefriendswithdifferentpeople.Takecareofyourcollections.Stampsareverydelicate.5Keepyourstampsinyouralbum集邮册aspecialbooktoprotectthem.Itmayhavepaperpagesorplasticoneswithpocketstoholdyourstamps.Nevertapeorglueyourstampsbecauseyoumaydamagethem.A.Therearesimplytoomanystamps.B.Anditisalsomeaningful.C.Theyarejustpiecesofpaperbuttheyhaveconsiderablevalueandsignificance意义非凡.D.Tryyourbesttocollectasmanystampsasyoucan.E.Gotogroupsandgatheringstoco﹣workwithpeople.F.Thinkcarefullywhatkindsofstampsyouwanttocollectwhenyoustart.G.Thatisaprimaryreason首要原因whyitisveryattractive吸引人comparedto相比之下othercollections.
果蝇的红眼与白眼灰身与黑身长翅与残翅细眼与粗眼均是由一对等位基因控制的相对性状且这四对基因位于三对同源染色体上．将纯种黑身残翅白眼雌蝇与纯种灰身长翅红眼雄蝇交配F1中雌蝇全为灰身长翅红眼雄蝇全为灰身长翅白眼F1中雌雄个体相互交配F2中灰身长翅黑身残翅≈31．回答下列问题 1眼色中为显性性状控制细眼和粗眼的基因位于染色体上． 2灰身与黑身长翅与残翅这两对性状的遗传填“遵循”或“不遵循”基因的自由组合定律上述实验F2中会出现少量的灰身残翅和黑身长翅的个体推测其原因最可能是． 3科研人员偶然发现了一只无眼的雌果蝇研究结果表明控制有眼和无眼的基因不位于上述三对同源染色体上请设计实验判断无眼性状的显隐性．．
紫花苜蓿是豆科多年生草本植物是我国主要的优质栽培牧草玉米是禾本科一年生作物．紫花苜蓿和玉米间作种植体系既能保证农牧交错区粮食产量满足家畜营养需求又能减轻该地区的风沙危害保护农田生态环境是一种环境友好型种植模式． 1在紫花苜蓿和玉米间作种植体系中二者株高不同对光能的利用有差别体现了群落的结构．流入植物体内的能量除呼吸作用以热能形式散失外另一部分用于． 2真菌AMF能与紫花苜蓿的根系建立生活体系．AMF从紫花苜蓿获取光合产物为紫花苜蓿提供无机盐．据此分析AMF属于生态系统组成成分中的与紫花苜蓿之间的种间关系是． 3此种植体系体现了生物多样性的价值．该体系的能力较强比单独种植紫花苜蓿和玉米的体系虫灾发生率低粮食和牧草产量均较高．
马的毛色由两对同源染色体上的等位基因控制其中一对同源染色体的相同基因位点在种群中有AtAa三种基因称为复等位基因相关表现型与基因组成的关系如表．如图是某育种场繁育马的系谱图请回答 1Ⅰ1Ⅰ2的基因型分别为． 2复等位基因AtA和a之间的显隐性关系是At对显性A对显性． 3Ⅱ1与Ⅱ3杂交后代中骝色马出现的几率为． 4如果要鉴定Ⅱ2的基因型可以让其与系谱中的杂交若杂交后代出现骝色马则Ⅱ2的基因型是若杂交后代出现褐骝色马则Ⅱ2的基因型是．
ShemustbethewisestwomanonthisplanetforshehasliveduptothethreewordsSeizethemoment.Toomanypeopleputoffsomethingthatbringsthemjoyjustbecausetheyhaven'tthoughtaboutitorbecausetheyareunwillingtotrysomethingnew. Mysisterdiedafewyearsago.Weneverdidhavelunchtogether.Ican'trememberhowmanytimesIwasrefusedwhenIcalledhertogotolunch.ShewouldsaytomeIcan't.Ihaveclothesontheline.Myhairisdirty.IwishIhadknownyesterday.Ihadalatebreakfast.Itlookslikerain.OnlyafterherdeathdidIchoosetobealittlemoreflexible. Lifeisnotmadeupofthingsthatyoudoataparticulartimebutitdemandsvarietyandadventure.Aswegrowolderthelistofpromisesmadetoourselvesmaygetlonger.PerhapsonemorningwhenweawakenwewillfindtooursurprisethatourlifeisfullofI'mgoingtoIplantoandSomedaywhenthingsaresettleddownabit. Myseizethemomentfriendisopentoadventureandreadyatanymomenttomakeanewstart.Shekeepsanopenmindaboutnewideas.Hergreatinterestinlifeiscontagious.Withheraroundyouyoumaytradeyourbadfeetforgoodshoes. Ihavenottouchedicecreamfor10years.TheotherdayIstoppedoffandboughtatripledecker.IfmycarhadhitanicebergonthewayhomeIwouldhavediedhappy. 1Thepassagesuggeststhattheauthor'ssister. A.wasverybusywithherwork B.diedaveryhappyperson C.alwaysdidthingsinafixedorder D.wasthewisestwomanintheworld 2Thewriterhashadanewwayoflookingatlifesince. A.hissisterdied B.hemetthewisewoman C.heturnedold D.thethreewordsappeared 3Theunderlinedwordcontagiousinthefourthparagraphisusedtoshowthatthewomanis. A.polite B.powerful C.practical D.proud 4Theauthorexpectsthosewhohavereadthepassageto. A.havealonglistofpromises B.beasmartbusinessman C.hitanicebergintheircars D.beasadventurousashimself
若图1图2图3是某同学做有丝分裂实验时在光学显微镜下观察到的图象下列有关说法正确的是
Televisionhasincreasedallthespeed1whichnewstravelsanditcanbringsituationsandimages场景和图象intoourhomesthatpreviousgenerations前辈wouldnothavehadtheopportunity机会towitness目睹Howdoestelevisionaffect影响ourlives?Itcanbe2helptothosewhocarefullychoosetheprogramsthattheywatchandharmfultothosewhowatchittoomuch.InChinamanypeopleworrythatkidsandyoungpeople3watchtoomuchtelevisionthesedays.4surveyof300youngstersinShanghailastyearshowedthatontheaverage平均下来theyspenthalfoftheirfreetime5istwoandahalfhourswatchingtelevisionandtwothirdsofanhour6readstories.Thestudentswhowatchedmanyhoursofentertainment娱乐programshad7lowtestscoresthanthosewhowatchedfewerhoursofsuchprograms.Anothersurvey调查ofschoolage8childinWuhanfoundthathalfofthemsaidtheyreadverylittle.DuringtheLondonOlympicGamestensofmillionsofChineseviewersstayeduplatetowatchtheopeningceremonyandotherprograms.Andtelevisionis9quicktakingtheplaceof10printmaterialasthemajorsource主要来源ofnewsformostChinese.
中国科学家成功突破了克隆猴这个世界生物学前沿的难题率先建立起可有效模拟人类疾病的动物模型实现了我国在非人灵长类研究领域由国际“并跑”到“领跑”的转变．据此冋答下列问题 1克隆猴的诞生体现了动物细胞的具有全能性．相对于植物组织培养而言动物尤其 是高等动物的克隆比较困难的原因最．克隆过程中一般利用未受精的去核卵细胞作为受体细胞原因是． 2克隆猴培养过程中需要用葡处理使细胞从瓶壁上分离下来．为了提高动物细胞克隆形成率可以选择适宜的培养基添加等天然成分以滋养细胞支持生长．培养箱中通常要维持一定的CO2浓度CO2的作用是．克隆猴除了用到动物细胞工程的相关生物技术手段外还必须用到答出两种技术．
Theyhaven'tformally宣布thedateoftheirweddingceremony.
关于生物变异的叙述正确的是
排乳是指哺乳或挤乳时反射性地引起贮存在腺泡和乳腺导管系统内的乳汁迅速排出体外的过程．如图表示排乳的部分调节过程．回答下列问题 1排乳过程的调节方式是．下丘脑细胞合成的催产素能运至垂体并暂时贮存暂时贮存的生理意义是． 2在排乳过程中泌乳素与催产素之间具有作用．泌乳素能作用于乳腺腺泡细胞是由于其细胞膜上分布有． 3催乳师通过按摩能解决产妇无乳乳少等问题据图分析其原因是．
Pattidiscoveredthemeaningofrunningwhenshewas23.Atthattimeshewassmokingtwopacksofcigarettes香烟adayandhad1weight﹣﹣﹣over30pounds.'Idecidedto2'shesays.Shetookaclockandstarted3whatshedideverydayandthenshe4anhouradayasa'benicetoPattihour'.'Istartedhavingbubble泡沫bathswith5litbecauseCosmopolitanMagazine6thatthiswouldbegoodforme.ButIgot7ofthatsoon'Pattiremembers.Shewantedtodosomethingreallypleasant.Shefoundthatthe8timesinherlifeweretimeswhenshewasphysicallyactive.Soshetookup9.Shedecidedtostart10thenextday.Sheranforanhour11atotalof7milesonherfirstrun.'Icouldn'twalkfortwoweeks12Ifeltpainfulallover!'Pattirecalls回忆.'ButIfeltsowonderful!'Pattiwasn'tcrazyaboutrunningyetbutshewasin13withtheaftereffectsofrunning.WithinsevenmonthsPattihadrunherfirstmarathonqualified有资格的fortheBostonMarathonandplaced25thintheworldfor14distancerunners.Overthenextyearsshe15recordsandsetstandardsforwomeninthesport.ShewasthefirstAmericanwomantoruna230marathonandthenbroke16tworecords17an8﹣monthperiod.Patti18thatifwecansetstandardsforourselveswecanpullourselvesoutofthemostdifficult19andcomeoutontop.'Everybodyhastobeachampionand20hasthatinthem.'1A.lost B.earned C.gained D.reduced2A.cry B.move C.walk D.change3A.striking B.recording C.sharing D.collecting4A.setaside B.setup C.setout D.setabout5A.lamps B.fires C.candles D.cigarettes6A.spoke B.said C.wrote D.went7A.afraid B.fond C.tired D.ashamed8A.saddest B.happiest C.loneliest D.luckiest9A.smoking B.bathing C.dieting D.running10A.right B.only C.even D.again11A.covering B.spreading C.passing D.overcoming12A.but B.although C.while D.because13A.peace B.line C.love D.touch14A.men B.women C.adults D.children15A.kept B.held C.broke D.cleared16A.another B.other C.else D.more17A.for B.on C.at D.over18A.believes B.imagines C.requires D.hopes19A.pleasures B.challenges C.pities D.purposes20A.anybody B.nobody C.somebody D.everybody
Thewaterisheavily污染bytheillegalchemicalcompany.
下列关于实验的叙述正确的是
文中共有10处语言错误每句中最多有两处.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\划掉. 修改在错的词下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. TodayisSunday.Ididn'tgetupearlyasusually.InthemorningafterIfinishedmyhomeworkIdosomewashing.ThenItelephonedoneofmyclassmateandinvitedhimtoseeafilm.Andunfortunatelywhenwegottothecinemaat300p.m.wefoundalltheticketshadsoldout.Sowewenttoourschoolandplayedthefootball.AfterthatwhenwewereabouttogohomewesawourEnglishteacherMr.Wangcameintotheschoolgate.HetolduswehadmademanyprogressinEnglishthisterm.Healsosuggestedthatweshouldreadmoreandwrotemore.Wepromisedthatwewouldtakehisadvices.
Theselfie自拍isnotnewmanypeoplehavealwaysproducedself﹣portraits自画像.PersonallyIdidn'tenjoyartatschoolbutIdidrememberthatwewerealwaysdrawingpicturesofourfaces.HoweverIthinkthisshowsjusthowoldtheself﹣portraitis.Theonlythingthathasreallychangedisthetechnologywhichweusetocreateself﹣portraits.Wehavegonefrompenciltothedigitalcamera数码相机.Thedigitalversion版本hasnowbecomeselfieawordnowsopopularthatitisnamedtheOxfordEnglishDictionaryOnline'sWordoftheYear. Traditionally按传统thebestwaytotakeaselfiewastostandinfrontofamirror.Thiswasfinethoughitdidlookalittlesillyasnomatterhowhardyoutriedyoucouldn'thidethecamera.Ofcoursephonesnowhavecamerasonboththebackandthefrontsoyoudon'tneedamirrortoguideyou.Thedrawback缺点tothismoremodernmethodisthatyoucanusuallyseethephotographer'sarminthephoto. Idon'treallyunderstandtheattractionoftheselfie.Takingaphotoofyourselfinthebathroomdoesn'tprovidethebestscenery提供最佳外景especiallyifyouforgettoputthetoiletseatdowngentlemen.Atfamoustouristattractions旅游景点italwayssaddens令人痛心metoseepeopletakeselfiestravellingonyourownisfinebutareyousomistrustfulofstrangers不信任陌生人thatyoucannotaskapasser﹣by过路人totakethephotoforyou? Howevertherehavebeenalotofarguments争论overtheselfie.RecentlyoneNewYorktouristtookaselfiewithamanthreatening威胁tocommitsuicide自杀ontheedgeofabridgebehindherandevenmorerecentlyBarackObamaalongwithDavidCameronandtheDanishprimeministerThorningSchmidttookagroupselfieatNelsonMandela'sfuneral丧礼. 1WhyisthewordselfienamedtheOxfordEnglishDictionaryOnline'sWordoftheYear A.Itcanbewritteninpencileasily. B.Itisveryimportantinthedictionary. C.Itmeansthedevelopmentoftechnology. D.Itisanewwordusedwidelyandpopularly. 2Whichofthefollowingisthedrawbacktothetraditionalwayoftakingaselfie? A.Therearearmsinthepicture. B.Thecameraisalwaysinthepicture. C.Thepictureisoftennotveryclear. D.Themirrorcanhardlybeavoided. 3Wecanlearnfromthelastparagraphthattheselfie. A.mayleadtocommitsuicide B.maybringunluckythingstous C.isnotsuitableatsomemoments D.ispopularontheledgeofabridge 4Whatdoestheauthorthinkofselfies? A.Politicalleadersshouldnottakeselfies B.Selfiescanpreventpeoplecommittingsuicide C.Itishardtoseewhyselfiesaresoappealing有吸引力 D.Itisnecessarytotakeselfieswhiletravellingalone
Thereisalarge可能性thatChinawillhostanotherbigevent.
Usingtoomuchwaterorthrowingrubbishintoourriversareclearwaysthathumanscanputourwatersupplyinlessobviousways.Youmaywonderhowpaving铺砌aroadcanleadtolessusablefreshwater.Amajorpartofthewaterweuseeverydayisgroundwater.Groundwaterdoesnotcomefromlakesorrivers.Itcomesfromunderground.Themoreroadsandparkinglotswepavethelesswatercanflowintothegroundtobecomegroundwater. Humanactivityisnotresponsibleforallwatershortages短缺.Areasofdrierclimatesareofcoursemorelikelytohavedroughts干旱thanoneswithmorerainfallbutinanycasegoodmanagementcanhelptomakesurethereisenoughwatertomeetourbasicneeds. Thinkingaboutthewayweusewatereverydaycanmakeabigdifferencetoo.IntheUnitedStatesafamilyoffourcanuse1.5tonsofwateraday!Thisshowshowmuchwedependonwatertolivebutthere'salotwecandotolowerthenumber. Youcantakestepstosavewaterinyourhome.Tostartwithusethesameglassforyourdrinkingwaterallday.Washitonlyonceaday.Runyourdishwasheronlywhenitisfull.Helpyourparentsfixanyleaksinyourhome.Youcanevenhelptokeepourwatersupplycleanbyrecyclingbatteriesinsteadofthrowingthemaway. 1Whichofthefollowingismostlikelytoleadtolessgroundwater? A.Usingriverwater. B.Throwingbatteriesaway. C.Pavingparkinglots. D.Throwingrubbishintolakes. 2Whatcanbeinferredfromthetest? A.Allwatershortagesarebecauseofhumanbehavior. B.Ittakesalotofeffortstomeetourwaterneeds C.Thereismuchwecandotoreducefamilysize. D.TheaveragefamilyinAmericamakesproperuseofwater. 3Thelastparagraphisintendedto. A.showushowtofixleaksathome B.tellushowtorunadishwasher C.provewhatdrinkingglassisbestforus D.suggestwhatwedotosavewaterathome 4Thetextismainlyabout. A.whypavingroadsreducesourwater B.howmuchwedependonwatertolive C.whydroughtsoccurmoreindryclimates D.howhumanactivityaffectsourwatersupply
KidPresidentsTruetales故事ofchildhoodfromAmerican'sPresidents ByDavidStablerillustratedbyDoogieHorner DECEMBER192014 ReviewedbyKidReporterSurajModi Gentre体裁Historicalnon﹣fiction纪实文学 Numberofpages224 What'sthebookabout? Inthe20storiesof20differentU.S.presidentsinthisbookwelearnthatthecountry'sleadersarenotsodifferentfromus.theytoowereoncekidswithordinaryproblems.Theystruggledwithschoolworkandangeredtheirparents.BillClintonstruggledwithhisweight.BarackObamamovedtoIndonesiawithhismotherwhenhewasjustaboyandhadtogetusedtoanewculture文化. Howdidtheauthormakethisbookinteresting DavidStablertellsstorieswithaninjectionofhumor以幽默的方式.Hetellstheunfamiliar鲜为人知storiesofthenation'sleadersuncoveringthejazzstarslifesaversandgoose﹣tamersamongthepresidents. Whowouldlikethisbook Youdon'thavetobeafanofhistorytopickupthisbook.Thosewhoenjoyreadingaboutovercomingstruggles克服困难butstillenjoyagoodbellylaughwouldlikethisbook.OfcourseifyouhopetobecomeafutureleaderoftheworldIsuggestyoureadthisbookcovertocover. Onascaleof1to1010beingbesthowwouldyouratethisbook? Iwouldratethisbooka10outof10becauseitisafantasticbook.IthaseverythingyoucouldaskforIt'seducationalfunnyandevenalittledramatic跌宕起伏的.Don'tlettheillustrations插图foolyou.Thisbookmayappeartobeforyoungreadersonlybutitisareadthewholefamilycanenjoy. 1WhentheAmericanpresidentswereyoungthey. A.showedtheirgreatness B.wereascommonasotherkids C.hadtroublegrasping领悟anewculture D.didn'tdotheirhomeworkatall 2Whoaremostlikelytobeinterestedinthebook? A.KidswhoaregoodatEnglish. B.Kidswhoaresuretobegreatinthefuture. C.Kidswhocanavoidhardstruggles. D.Kidswhoareeager渴望tobeasuccessfulleader. 3SurajModithinksthatthebook. A.isaperfectonefortheyoungandthewholefamily B.cansellprettywellinthemarket C.costspeoplealargeamountofmoney D.canbeusedasatextbookatschool
某小组利用草莓对影响光合作用的因素及果实发育期光合产物的转移进行了相关实验．图1表示在最适温度及其它条件保持不变的条件下草莓叶片CO2释放量随光照强度变化的曲线图2表示在适宜条件下向密闭温室中充入一定量14CO2后草莓叶片茎果实的放射性含量随时间变化的曲线．请回答下列问题 1图1中B点时叶肉细胞中产生的O2的扩散路径是．C点骤变为D点时短时间内三碳化合物的含量将．E点后曲线保持水平不变此时限制草莓光合作用速率的主要环境因素是． 2由图2可知t1～t2时间段叶片中有机物的含量下降．最可能的原因是．
Youcangetafreebike方便地asmanyfree﹣bikestationsaresetupinthecity.
高温胁迫是影响植物生长发育的重要因素之一高温会使番茄的生长发育受到限制．科学家将来自土壤细菌中的codA基因转入番茄使番茄对高温的耐受性大于野生型番茄．回答下列问题 1过程①获得的DNA片段填“可以”“部分可以”或“不可以”实现物种间的基因交流．采用PCR技术扩增codA基因时操作过程中需要加热至90～95℃的目的是． 2去磷酸化是去掉黏性末端最外侧游离的磷酸基团过程③对已开环的质粒两端去磷酸化的主要作用是为使codA基因在受体细胞中表达需要将其插在启动子之后目的是． 3过程④最常用的方法是过程⑤用到的细胞工程技术是．codA基因能否在番茄细胞中稳定遗传的关键是．
Thepolicecaughtthree嫌疑犯frominformationprovidedbyacitizen.
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