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为了从甲、乙两组中选一组参加“喜迎国庆，共建小康”知识竞赛活动，班主任老师将两组最近的6次测试的成绩进行统计，得到如图所示的茎叶图．若甲、乙两组的平均成绩分别是，，则下列说法正确的是（ ）
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高一下学期数学《》真题及答案
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在如图所示的茎叶图中乙组数据的中位数是若从甲乙两组数据中分别去掉一个最大数和一个最小数后两组数据的平
甲乙两组数据如下甲组1091181213107乙组7891011121112.分别计算出这两组数据的
为了判断甲乙两个小组学生英语口语测验成绩哪一组比较整齐通常需要知道两组成绩的
将含有甲乙丙的6人平均分成两组参加文明交通志愿者活动其中一组指挥交通一组分发宜传资料则甲乙至少一人
为了甲乙丙三位同学中选派一位同学参加环保知识竞赛老师对他们的五次环保知识测验成绩进行了统计他们的平均
有甲乙丙丁四个小组进行拔河比赛比赛结果是①当甲乙两组联合为一方丙组和丁组为一方时双方势均力敌②当甲组
甲、乙、丙、丁
丙、乙、丁、甲
乙、甲、丙、丁
丁、乙、甲、丙
某校举办了一次知识竞赛满分10分学生得分均为整数成绩达到6分以上包括6分为合格达到9分以上包括9分为
已知甲乙两组数据的平均数相等如果甲组数据的方差为0.055乙组数据的方差为0.105则
甲组数据比乙组数据波动大
甲组数据比乙组数据波动小
甲、乙两组数据的波动一样大
甲、乙两组数据的波动不能比较
有甲乙丙丁四个小组进行拔河比赛比赛结果是①当甲乙两组联合为一方丙组和丁组为一方时双方势均力敌②当甲组
甲、乙、丙、丁
丙、乙、丁、甲
乙、甲、丙、丁
丁、乙、甲、丙
甲乙两位学生参加数学竞赛培训在培训期间他们参加5次预赛成绩记录如下甲7876749082乙90707
甲乙两位学生参加数学竞赛培训.现分别从他们在培训期间参加的若干次预赛成绩中随机抽取8次记录如下甲82
甲乙两位学生参加数学竞赛培训现分别从他们在培训期间参加的若干次预赛成绩中随机抽取8次记录如下甲828
甲乙两位学生参加数学竞赛培训.现分别从他们在培训期间参加的若干次预赛成绩中随机抽取8次记录如下甲82
甲乙两位学生参加数学竞赛培训.现分别从他们在培训期间参加的若干次预赛成绩中随机抽取8次记录如下甲82
甲乙两位学生参加数学竞赛培训在培训期间他们参加的5次预赛成绩记录如下甲乙1用茎叶图表示这两组数据2从
甲乙两位学生参加数学竞赛培训在培训期间他们参加了5次预赛成绩记录如下甲7876749082乙9070
甲乙两位学生参加数学竞赛培训在培训期间他们参加了5次预赛成绩记录如下甲8282799587乙9575
有供实验用的3组番茄甲乙两组在开花前进行去雄和套袋甲组在套袋之前将雌蕊涂抹了一定浓度的生长素溶液丙组
某班级从甲乙两位同学选派一人参加数学竞赛老师对他们平时的10次模拟测试成绩单位分进行了记录如下甲79
为了判断甲乙两组学生英语口语测试成绩哪一组比较整齐通常需要知道这两组成成绩的
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油菜素内酯BR可提高水稻对真菌细胞壁成分为几丁质的抗性．为研究其分子机制科研工作者用BR对水稻进行了处理并检测了实验组和对照组水稻叶片几丁质酶的活性结果如图1所示同时提取了实验组和对照组水稻细胞中总RNA进行反转录并对其产物进行PCR后电泳处理结果如图2所示18S为参照．据图分析下列说法不正确的是
镉Cd是一种重金属镉污染会造成植物叶绿素含量下降生长不良．为探究镉对植物生长发育的影响科研人员利用黑麦草进行实验结果如图．请回答下列问题 1随着镉浓度的增加活性氧含量增加使叶绿体中的膜受到破坏叶绿素含量下降导致吸收的光明显减少光合作用强度下降． 2镉导致叶绿素含量下降的另一个原因是根系对Mg2+的吸收能力下降．请结合图中数据分析镉降低根系对Mg2+吸收能力的机理 ①随镉浓度的增加H+﹣ATP酶活性下降导致受抑制细胞能量供应减少． ②活性氧含量增加受损加剧导致细胞运输Mg2+的载体减少． 3利用CdCl2完全培养液黑麦草以及其它所需的材料和设备在不破坏植物组织前提下设计实验验证随镉浓度的增加根系对Mg2+的吸收能力下降．请写出实验思路．
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他采取了医生的建议:他应将均衡的饮食和有规律的锻炼相结合.同位语从句combine
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他设法阻止了他儿子独自去游泳.managepreventfrom
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ManyyearsagoIworkedonamidnightshift夜班inahospitalinIndiana.Iwas1moneytogobacktocollege.Someofthepeopleonthatshiftcouldbe2.whichworemedownandmademelessdetermined.3therewasonewomanwhowasvery4andalwayssokindOther5wouldwanttotalktoheronbreaksbecausetheywouldleavefeelingmuch6. BecauseofmyAsperger'sSyndrome阿斯伯格综合症Iwas7somebasicsocialskillslikecommunicationcausingmuch8inmydailylife.Luckilysheshowedgreatcareandacceptedthemistakesone9makesinhisearlyteens.The10sheshowedhelpedmefigureoutwhattodonext.AndI11adifficulttimewhenlifewasverydarkforme.Ireturnedtoschooltocontinuemy12andgraduatedatlast. I'vefelt13topassherkindnessontoothersandIhavetriedtodoso.Hersmall14ofkindnesshasbeenrepaidmanytimes.Wehavetwo15inlife:kindnessorviolence.Eitherisagiftthatkeepsongiving.Whenyouknowthatyourgiftswillberepaidmorethanabilliontimesdoesn'tthechoiceseem16? Ichoosekindnesswheneverpossible.Idonot17anyofthechoicesI'vemadefromkindness.ButIdofeelsorryformanyofthechoicesImadefromviolence.IwishIcould18thatwomannowthoughIhavenoideawheresheis.Shehas19mylifeinawaythatshe'llneverknow.Andnowtheripples涟漪ofherkindness20throughmetomanyothers. 1A.collecting B.borrowing C.earning D.paying 2A.unlucky B.sensitive C.stubborn D.unfriendly 3A.Besides B.However C.Thus D.Indeed 4A.grateful B.cheerful C.doubtful D.forgetful 5A.strangers B.patients C.schoolmates D.workmates 6A.better B.healthier C.braver D.smarter 7A.tiredof B.shortof C.curiousabout D.concernedabout 8A.trouble B.danger C.violence D.loss 9A.suddenly B.finally C.normally D.gradually 10A.devotion B.satisfaction C.kindness D.forgiveness 11A.steppedinto B.sortedout C.cameacross D.pulledthrough 12A.research B.education C.performance D.exploration 13A.moved B.relaxed C.relieved D.surprised 14A.topic B.gift C.habit D.tip 15A.opinions B.chances C.beliefs D.choices 16A.clear B.funny C.foolish D.brief 17A.regret B.forget C.expect D.refuse 18A.please B.admire C.thank D.help 19A.ruined B.controlled C.designed D.affected 20A.burst B.float C.flow D.jump
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Eventhougharecentstudyshowsnapping小睡hassomethingtodowithhigherdeathratescompaniesandcollegesacrosstheU.S.aresettingupnaproomstoincreaseefficiency效率.Trulyitwouldbeadreamtoreachanagreementonnapping. Butwhetherornotnappingisrightforyoudepends.Firstofallit'simportanttoaskyourselfwhyyou'retakingthenapsaysDr.SaraMednickapsychologistattheUniversityofCalifornia.Ifyou'respendingmuchofyourdayfeelingsleepythenyourdesiretonapmaybedrivenbystressorotherhealthconditionsthatbadlyaffectyoursleepMedmcksays. DaytimenappingisanearlysignofpossibleillhealthaddsYueLengaUniversityofCambridgesleepresearcher.LikeMednickhesuggestsdaytimesleepinessislikelyasignofotherhealthproblemsnottheircause. Putsimplyblaming指责napsforhigherdeathratesislikeblamingyourdoctorforheartdisease;you'remorelikelytoseeadoctorifyouhaveheartproblemsbutthatdoesn'tmeanshe'stoblame. ActuallynapsaregoodformostpeopleMednicksays.Herresearchshowsanapcanimprovebrainfunctionsrangingfrommemorytofocusandcreativity.Moreresearchshowsaquicknapcanlowerstressandrechargeyourwillpower.ButallofthesebenefitsdependonyougettingagoodnightofsleeptobeginwithMednickstresses. Howevernoteveryoneisagoodnapper.Somepeoplewakeupfromnapsfeelingterribleshesays.Ifyou'veneverbeenanapperbutwanttocashinonnapping'sbrainandhealthbenefitsMednicksaysyoumaybeabletoteachyourselftonap.Thetrickistokeepyourdaytimeshuteyeveryshort﹣nomorethan15minutesatfirst.Thiswillstopyourbrainandbodyfromfallingintothedeeperlevelsofsleepthatleaveyoufeelingfoggyuponwakingsheadds. Butifyou'rejustnotabornnapperdon'tsweatit.Everyone'sdifferentMednicksays.Ifyoufeelgoodwhateveryou'redoingisfine. 1ResearchersMednickandYueLengboththinkthatnappingcan. A.mirrorhealthproblems B.increaseworkefficiency C.causehigherdeathrates D.improvehealthconditions 2Whatdoestheauthorthinkofpeople'sblamingnapsforhigherdeathrates? A.Impolite. B.Necessary. C.Improper. D.Acceptable. 3TheunderlinedphrasecashinoninParagraph6probablymeans. A.applyfor B.takeadvantageof C.standfor D.taketheplaceof 4AccordingtoMednickthosewhoarenotbornnappersshould. A.takeiteasy B.shortensleeptime C.giveitatry D.improvesleepquality
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在过去四十年中国发生了巨大的变化我们对此感到无比自豪.takeplace'介词+关系代词'定语从句
InJanuary2010apolicemanMichaelMalarsiewasondutyinAfghanistanwithothermemberswhenoneofthemsteppedonanIntelligentElectronicDeviceIEDburiedintheground.Itexplodedhittinghimintheface. TwoweekslaterhewokeupatWalterReedArmyMedicalCenter.MalarsierecalledhisfatherpushinghiminawheelchairtospeakwithadoctorwhotoldhimI'msorrywetriedbutthere'snothingwecando.You'regoingtobetotallyblind. TheexplosiondestroyedhiseyesightbutMalarsiewhowas22atthetimerealizedhowluckyhewastobealive.Theexplosionchangedmywholelife.Iwasn'tgoingtoletblindnessslowmedownhesaid. OneofthefirstthingsIthoughtofwasaguidedogMalarsiesaidsoheappliedforonewithFidelcoacharitableorganizationinConnecticutandaleadingprovideroftrainedguidedogs.Butoneofthosefour﹣leggedhelperscostabout﹩45000﹣notexactlyanaffordablepriceforanAirForceveteran老兵withafamily.・That'swhereNewman'sOwncamein﹣providingsomemoneythathelpedconnectMalarsiewithhisguidedog. OneyearlateraftertheexplosionMalarsiegotXxonayoungGermanshepherd.XxonhasgivenmebackthefreedomindependenceandconfidencetodowhatIneedtobeabletodohesaid.IthinkwhenyouhearaboutwhatNewman'sOwndoesonabroadrange范围it'shardtounderstandtheinfluencethatithas.・It'sonethingtohearadollaramountbutit'sawholeotherthingwhenyouhearthestoryofsomeonewho'spersonallybeenaffected.MylifehaschangedforeverMalarsieadded. Forover30yearsNewman'sOwnhashelpedsupportthousandsofcharitablecausesandorganizationswithclosetohalfabilliondollarsbeingdonatedsinceitsfoundingin1982.EverytimeyoubuyaNewman'sOwnproductyoustartajourneytowardimprovingsomeone'slife﹣someonelikeMichaelMalarsie. 1WhydidMichaelMalarsiebecomeblind? A.HesetoffanIEDbyaccident. B.Anexplosionhithimintheface. C.AfellowblewupanIEDonpurpose. D.Thedoctorsdidn'ttreathimproperly. 2HowdidNewman'sOwnhelpMichaelMalarsie? A.Byteachinghimbasiclifeskills. B.Bytrainingaguidedogforhim C.Byencouraginghimtobeconfident. D.Byofferinghimsomefinancialhelp. 3WhatcanweinferaboutNewman'sOwnaccordingtoParagraph5? A.Ithasmanyinterestingstories B.Itsinfluenceremainstobeseen C.Itmeansmuchtothoseinneed D.Itsactionisdifficulttounderstand.
建立生态农业和对被破坏的自然生态系统进行恢复实现了自然经济社会持久而协调的发展．请回答下列问题 1建立生态农业可以将秸秆作饲料喂牲畜牲畜粪便进入沼气池发酵产生的沼气作燃料沼渣用来肥田．沼渣肥田可以促进生态系统的功能．牲畜粪便中的能量属于填“第一营养级的同化量”“第二营养级的同化量或“第二营养级传递给分解者的能量” 2豆科植物与根瘤菌的种间关系为．生态农业往往选择豆科植物和玉米小麦等农作物进行轮作主要目的是．生态农业控制害虫数量时往往通过喷施性引诱剂干扰昆虫交尾性引诱剂属于信息该实例说明离不开信息传递． 3人类对受到严重破坏而退化的草原和森林生态系统进行恢复主要利用的是理论在不同的阶段种植不同的植物并采用生态工程的办法使其恢复到正常状态．
环境污染物多聚联苯难以降解受其污染的土壤中常有重金属污染同时存在．研究发现联苯降解菌内的联苯水解酶是催化多聚联苯降解的关键酶．回答下列问题 1为了从富含多聚联苯的环境中分离联苯降解菌培养基中加入多聚联苯作为该培养基属于填“选择”或“鉴定”培养基．用平板划线法纯化该细菌时第2次划线及其以后划线总是从上次划线的末端开始是为了． 2为了能够反复利用联苯水解酶可以采用技术该技术的另一个优点是． 3若从联苯降解菌中分离并得到纯度较高的联苯水解酶纯化该酶常用的方法是采用该方法先分离出分子质量的蛋白质． 4如图实线表示联苯水解酶催化的反应速度与酶浓度关系虚线表示在其他条件不变情况下底物浓度增加一倍反应速度与酶浓度的关系能正确表示两者关系的是
Batsaretheonlymammalsthatcanflyagreatdistancebuttheyhaveanotherability.Manybatsliveaverylongtimeforananimaltheirsize. Europeanresearchersarestudyingbatstounderstandwhytheylivesolong.Theyhopetomakediscoveriesaimedatfightingtheagingprocessinhumanbeings.Lastweekthegroupofscientistssaidtheyhadidentifiedimportantbiologicalqualitiesinsomebatspecies. Thegroupstudiedbatchromosomes染色体alineofgenesfoundinthenucleusofcells.Thescientistsweremostinterestedinstructuresconnectedtotheendsofthechromosomes.Theyarecalledtelomeres.Telomeresprotecttheendsofchromosomeswhichshorteneachtimeacelldivides.Scientistsbelievethisshorteningprocesscausescellstobreakdown.Theysaythisiswhatcausesaging. TheEuropeanresearchersstudied493batsfromfourbatspecies.Thegroupusedinformationthathadbeengatheredovermorethan60years.Oftheseanimalsthegreatermouse﹣earedbatgenerallylivedthelongestanaverageof37years.ThescientistssaidthisandarelatedspecieswhicharegroupedtogetherunderthenameMyotishadtelomeresthatdidnotshortenwithage. Thescientists'findingssuggestthatthesebats'cellshavetheabilitytomaintainandrepairtheirtelomeres.Thistheysaidhelpsguardagainsttheagingprocess. Basedonitsbodysizeabatlikethegreatermouse﹣earedbatwouldbeexpectedtolivefouryears.Butthesemammalshavebeenfoundtolivenearly10timeslongerthanthat. 1Whichthefollowingstatementisrightaccordingtothetext? A.Batslivethelongesttimeamonganimals. B.Europeanresearcherswanttofighttheagingprocessinhumanbeing. C.Fromtheinformationscientistsfoundthegreatermouse﹣earedbatlivedthelongestlifeinallspecials. D.Scientistshavedevelopedwaystofightagingbystudyingbats. 2Accordingtothescientiststelomeresare? A.structureswhichprotecttheendsofchromosomes. B.geneswhichcanbefoundinthenucleusofcells. C.chromosomeswhichcanshorteneachtimeacelldivides. D.agingprocesses. 3AccordingtothetextMyotishadthelongestlifeamongbatsspeciesbecause? A.theyhadtelomeresthatkeepageprocessing. B.theircellscanmaintainandrepairtheirtelomeres. C.theirchromosomesweremorethanothers. D.theirtelomerescausecellstobreakdown
生态位表示生态系统中每种生物生存所必需的生境最小阈值．在自然环境里每一个特定位置都有不同的生物其活动以及与其它生物的关系取决于它的特殊结构生理和行为故具有自己的独特生态位． 1据生态位内涵可知每种生物占有各自的空间在群落中具有各自的功能和营养位置以及在温度湿度土壤等环境变化梯度中所居的地位．一个种的生态位是按其来确定的． 2在某时期内该草场蝗灾严重为了掌握灾情对该草场的几种蝗虫的种群密度进行调查结果如图所示 ①调查某种蝗虫若虫跳蝻的种群密度可采用法．该实验的自变量是根据实验结果可建立模型．当蝗虫密度小于15只/m2时虫采食不能促进牧草再生长． ②为避免农药灭蝗虫带来的环境污染现在实行大面积施用蝗虫微孢子虫蝗虫的寄生虫可以很好的控制蝗灾此方法属于防治．该草原群落的是区别不同草原群落的重要特征．
假定你是李华.你从互联网上得知第十二届国际未来商业领袖峰会InternationalFutureBusinessLeaderSummit将在上海举行并欢迎中学生参加.请你写一封电子邮件申请参加.要点如下: 1.自我介绍包括英语能力; 2.申请参加活动的意图增长商业知识提高领导力加强交流; 3.希望获准. 注意:1.词数80左右; 2.可适当加入细节使内容充实行文连贯.
ARaceAgainstDeath ItwasacoldJanuaryin1925inNomeAlaska.Thetownwascutofffromtherestoftheworldduetoheavysnow. Onthe20thofthatmonthDr.Welch1asickboyBillyandknewhehaddiphtheriaadeadlyinfectious传染的diseasemainlyaffectingchildren.ThechildrenofNomewouldbe2ifitstruckthetown.Dr.Welchneededmedicineassoonaspossibletostopotherkidsfromgettingsick.3theclosestsupplywasover1000milesawayinAnchorage. HowcouldthemedicinegettoNome?Thetown's4wasalreadyfulloficesoitcouldn'tcomebyship.Carsandhorsescouldn'ttravelonthe5roads.Jetairplanesandbigtrucksdidn'texistyet. 6January26Billyandthreeotherchildrenhaddied.Twentymorewere7.Nome'stownofficialscameupwithan8.Theywouldhavethemedicinesentby9fromAnchoragetoNenana.Fromtheredogsled狗拉雪橇drivers﹣knownasmushers﹣would10ittoNomeinarelay接力. TheracebeganonJanuary27.ThefirstmusherShannonpickedupthemedicinefromthetrainatNenanaandrodeallnight.11hehandedthemedicinetothenextmusherShannon'sfacewasblackfromtheextremecold. OnJanuary31amushernamedSeppalahadto12afrozenbodyofwatercalledNortonSound.Itwasthemost13partofthejourney.NortonSoundwascoveredwithicewhichcouldsometimesbreakupwithoutwarning.IfthathappenedSeppalamightfallintotheicywaterbelow.Hewould14andsowouldthesickchildrenofNome.ButSeppalamadeitacross. AhugesnowstormhitonFebruary1.AmushernamedKaasenhadtobravethisstorm.Atonepointhugepilesofsnowblockedhis15.Hehadtoleavethetrail雪橇痕迹togetaroundthem.Conditionsweresobadthatitwasimpossibleforhimto16thetrailagain.TheonlyhopewasBaltoKaasen'sleaddog.Baltoputhisnosetotheground17tofindthesmellofotherdogsthathadtraveledonthetrail.IfBaltofaileditwouldmeandisasterforNome.Theminutespassedby.SuddenlyBaltobeganto18.Hehadfoundthetrail. At5:30amonFebruary2Kaasenandhisdog19inNome.WithinminutesDr.Welchhadthemedicine.Hequicklygaveittothesickchildren.Allofthemrecovered. Nomehadbeen20. 1A.examined B.warned C.interviewed D.cured 2A.harmless B.helpless C.fearless D.careless 3A.Moreover B.Therefore C.Otherwise D.However 4A.airport B.station C.harbor D.border 5A.narrow B.snowy C.busy D.dirty 6A.From B.On C.By D.After 7A.tired B.upset C.pale D.sick 8A.plan B.excuse C.message D.topic 9A.air B.rail C.sea D.road 10A.carry B.return C.mail D.give 11A.Though B.Since C.When D.If 12A.enter B.move C.visit D.cross 13A.shameful B.boring C.dangerous D.foolish 14A.escape B.bleed C.swim D.die 15A.memory B.exit C.way D.destination 16A.find B.fix C.pass D.change 17A.pretending B.trying C.asking D.learning 18A.run B.leave C.bite D.play 19A.gathered B.stayed C.camped D.arrived 20A.controlled B.saved C.founded D.developed
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