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某同学查得弹性势能表达式为Ep＝kx2，式中k是劲度系数，x是形变量（压缩量或伸长量）．某兴趣小组设计了如下的实验来验证弹性势能大小与形变量的关系 （1）提供的器材：刻度尺、木板、木块、长度不同的...
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高三下学期物理《》真题及答案
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当今流行一种蹦极运动如图所示在距河面45m高的桥上A.点系弹性绳另一端B.点系住重50kg男孩的脚弹
某同学探究弹性势能的表达式他猜测弹簧的弹性势能E.P.与弹簧的劲度系数k及弹簧的形变量x有关于是他认
根据E.
P.
、k、x 的国际单位，可以确定a 、b、 c的值
根据E.
P.
、k、x 的国际单位，可以确定a 、c的值
根据E.
P.
、k、x 的国际单位，可以确定a 、b的值
根据E.
P.
、k、x 的国际单位，可以确定b、 c的值
某同学探究弹性势能的表达式他猜想弹簧的弹性势能EP与弹簧的劲度系数k及弹簧的形型变量x有关．于是他认
根据E
P
，k，x的国际单位，可以确定a，b，c的值
根据E
P
，k，x的国际单位，可以确定a，c的值
根据E
P
，k，x的国际单位，可以确定a，b的值
根据E
P
，k，x的国际单位，可以确定b，c的值
因为手边没有天平小王同学思考如何利用一已知劲度系数为k的弹簧和长度测量工具来粗测一小球的质量.他从资
如图所示轻质弹簧的劲度系数为k小球所受重力为G.平衡时小球在
处.今用力F.竖直向下压小球使弹簧缩短x，让小球静止在
处，则 A.小球在A.处时弹簧的弹力为零 B.小球在B.处时弹簧的弹力为kx
小球在A.处时弹簧的弹性势能较大
小球在B.处时弹簧的弹性势能较大
因为手边没有天平小王同学思考如何利用一已知劲度系数为k的弹簧和长度测量工具来粗测一小球的质量他从资料
小玲同学平时使用带弹簧的圆珠笔写字她想估测里面小弹簧在圆珠笔尾端压紧情况下的弹性势能的增加量.请你帮
如图所示质量为M的长滑块静止在光滑水平地面上左端固定劲度系数为k且足够长的轻质弹簧右侧用一不可伸长的
写出一个图象经过一三象限的正比例函数y＝kxk≠0的表达式关系式________________.
在弹性限度内弹簧的弹力大小与弹簧的伸长量成正比即F.=kx其中F.为弹力大小x为伸长量k为弹簧的劲度
10cm
15cm
20cm
25cm
已知正比例函数y=kxk≠0的图象经过点﹣12则这个函数的表达式为
如图所示在动摩擦因数μ=0.2的水平面上有一质量为m=3kg的物体被一个劲度系数为k=240N/m的
通过先设定函数表达式确定函数模型再根据条件确定表达式中的未知系数从而求出函数的表达式的方法称为___
在弹性限度内弹簧的伸长量与受到拉力成正比其表达式为F=KX其中F为拉力X为弹簧伸长量K为弹簧的劲度
如果函数的表达式是自变量的________那么这样的函数称为一次函数它的一般形式是_________
因为手边没有天平小王同学思考如何利用一已知劲度系数为k的弹簧和长度测量工具来粗测一小球的质量他从资料
某缓冲装置可抽象成如图所示的简单模型图中K1K2为原长相等劲度系数K1＞K2的两根轻质弹簧开始时两弹
缓冲效果与弹簧的劲度系数无关
垫片向右移动时，K
1
产生的弹力大于K
2
产生的弹力
垫片向右移动时，K
1
的长度大于K
2
的长度
垫片向右移动时，K
1
弹性势能增大，K
2
的弹性势能减小
如右图所示一倾角为θ＝30°的足够长固定光滑斜面底端有一与斜面垂直的固定挡板M.物块A.B.之间用一
如图所示轻质弹簧的劲度系数为k小球所受重力为G平衡时小球在A处．今用力F竖直向下压小球使弹簧缩短x让
小球在A处时弹簧的弹力为零
小球在B处时弹簧的弹力为kx
小球在A处时弹簧的弹性势能较大
小球在B处时弹簧的弹性势能较大
某同学在探究弹簧的弹性势能与弹簧形变量的关系时猜想弹簧的弹性势能不仅跟形变量有关也应跟弹簧的劲度系数
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某同学为探究不同物质及浓度对洋葱表皮细胞失水的影响设计了如下实验．请回答 步骤1配制具有一定浓度梯度的蔗糖和氯化钠溶液各10mL分别加入培养皿中加盖编号． 步骤2从同一紫色洋葱鳞片叶的相同部位撕取外表皮若干迅速分别投入到上述培养皿中使其完全浸入溶液浸泡10min． 步骤3依次取出洋葱鳞片叶外表皮制成临时装片用显微镜观察并拍照． 步骤4统计照片中细胞总数及质壁分离细胞数计算质壁分离细胞占比结果如图． 1步骤1中培养皿加盖的目的是．步骤3中制作临时装片时需在载玻片中央滴加1～2滴． 2实验表明当两种溶液的浓度低于0.2mol•L﹣1时洋葱表皮细胞几乎不发生质壁分离原因是．在0.4mol•L﹣1蔗糖溶液中大约只有20%的细胞发生了质壁分离同一表皮的细胞质壁分离不同步的原因是． 3根据实验结果分析0.6mol•L﹣1NaCl溶液的渗透压比0.6mol•L﹣1蔗糖溶液的渗透压． 4在“观察植物细胞质壁分离及复原实验”中一般认为使材料中50%左右的细胞发生质壁分离的溶液浓度为理想实验浓度因为用该浓度溶液进行实验不宜选用0.35mol•L﹣1NaCl溶液进行实验的理由是．
Thechoirrehearsal合唱排练oftheschoolyeartookplaceintheschoolhall.Allthestudents1 togethertosing.Iwatchedasmyeldersisterandhergradetooktheirplacesonthe2MeanwhileIcouldhearsomestudentslaughingand3atagirlnexttomysister.I'dneverseenthisgirlbefore.Agirl4inmyearDoyouknowshe's5diapers纸尿裤? AfterschoolthateveningIaskedmysisteraboutthegirlthatIsaw.ShetoldmehernamewasTheresaandthatshewasanicegirl.Whywerethosekidsbeing6toher?Iasked.Becausethey're7shesaid. OnedayIwaswalkinghomefromschoolwhenIheardvoicesbehindmeThere'sthelittleidiot's白痴的youngsister.Doesyoursisterwether8too?Iwalkedfasterandthenfeltastone9meintheback.WhenIgothomeIpushedmywayintoherroom10atherWhydoyouhavetobethatgirl's11?Idon'tseeanyoneelsebeing12toher.JanelleyelledbackBecauseshe'sawonderfulpersonandshe's13!Iwillrememberthosewords14Ilive.Theresawettedhertrousersbecauseshehadan15whichwaskillingher.Mysistertheonlyoneniceenoughtobeherfriendandstickupforher.Severalmonths16Theresa17. Ifelt18thatJanellewasmysister.Throughouttheyearsshealwaysmadefriendswitheveryone.Itdidn'tmatterwhethertheywerebrilliantornot?Sheneverleftanyonefeeling19.Itwasshewho20meandtaughtmenevertolookatanyoneinthesamewayagain. 1A.pulled B.joined C.lived D.crowded 2A.stand B.room C.stage D.bench 3A.pointing B.glaring C.aiming D.glancing 4A.threw B.yelled C.shouted D.whispered 5A.wearing B.dressing C.putting D.carrying 6A.kind B.friendly C.rude D.merciful 7A.interesting B.polite C.generous D.stupid 8A.trousers B.shoes C.socks D.coat 9A.beat B.hit C.blocked D.touched 10A.glaring B.screaming C.staring D.talking 11A.friend B.classmate C.singer D.teacher 12A.tough B.nice C.terrible D.cruel 13A.arriving B.approaching C.dying D.recovering 14A.atthesametime B.themoment C.aslongas D.assoonas 15A.problem B.dream C.kindness D.illness 16A.ago B.before C.away D.later 17A.diedout B.becamewell C.fadedout D.passedaway 18A.disappointed B.shamed C.proud D.ashamed 19A.wise B.alone C.awesome D.fearful 20A.changed B.scared C.developed D.improved
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酵母菌是常用的生物实验材料相关叙述正确的是
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Keepingadiaryisoneoftheuseful1waytoimproveourEnglishability. 2comparewithotherformsofwritingitisshorterandtakes3littletime.ItcanhelpustodevelopthehabitofthinkinginEnglish.Ifwepersistinthispracticegraduallywe'lllearnhowtoexpress4weinEnglish.WekeepadiaryinEnglish5canhelpusdealwithmanydifficulties.Inthefirstplaceitoftenhappensthatwehavetrouble6findproperwordsandphrasestogiveexpressionstoourmind.SecondlytherearemanyidiomaticwaysofsayingthingsinChinese.Andit's7extremehardforustoputthemintoEnglishproperly. ManyyearsagomyEnglishteachercameupwithasuggestionthateverystudent8haveanotebookandaChinese﹣Englishdictionarywithineasyreach.Wheneversomethingbeatsuswecanfirstputitdowninournotebookandthenconsultourdictionary.WecanalsoaskourEnglishteacherforhelpifnecessary.InshortIbelievethatitis9greatusetokeepadiaryinEnglishfor10developmentofourwritingskills.
利用科学记数法表示的数原来各是什么数7.04×106=
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ThesuiciderateinAmericaisupby18%since2000.Thisisnotmerelyatragedy;itmatterspoliticallytoo.Theriseislargelyamongwhitemiddle﹣agedpoorlyeducatedmeninareasthatwereleftbehindbyboomsandcrushedbybusts.Theirdeathsareasymptomoftroublesthatshouldnotbeignored. NonethelessbeyondAmerica'sgloomytrendisamoreoptimisticstory:thatatagloballevelsuicideisdownby29%since2000.Asaresult2.8mliveshavebeensavedinthattime﹣threetimesasmanyashavebeenkilledinbattle.Thereisnoonereason.Itishappeningatdifferentratesamongdifferentgroupsindifferentplaces. Whyarepeoplenowlesslikelytotaketheirownlives?Urbanizationandgreaterfreedomhavehelped.AccountsofthosewhoattemptsuicideandoftherelativesofthosewhosucceedsuggestthatmanyyoungAsianwomenweredriventodespairbyviolenthusbandsandoverbearingin﹣laws.Aspeoplemovetocitiesandthegripoftraditionloosenswomenhavemorechoiceaboutwhomtheymarryorlivewithmakinglifemorebearable.Leavingthevillagehelpsinanotherwaytoo.Becausefarminginvolveskillingthingsruralfolkarelikeliertohavethemeanstokillthemselves﹣gunspesticides﹣tohand. Effortstocontrolaccesstothemeanstokilloneselfcanhelptoo.Suicideissurprisinglyimpulsive.AstudyofyoungChinesewomenwhohadtriedtokillthemselvesshowedthatthree﹣fifthshadbeencontemplatingsuicideforlessthantwohoursandoneintenforlessthanaminute.Of515peoplewhohadsurvivedtheleapfromSanFrancisco'sGoldenGateBridgebetween1937and197194%werestillalivein1978﹣whichsuggeststhatasuicidepostponedislikelytobeasuicideprevented. 1Whichisnotthereasonofsuicidedecreasing? A.Morefreedom B.Moreforcedmarriages C.Urbanization D.Morecontrolonmeans 2Wecaninferfromparagraph4that A.manypeopledecidedtokillthemselvesafteraseriousconsideration B.about484peoplestillalivein1978aftersurvivingtheleapbetween1937and1971 C.515peopletriedtosuicidebyjumpingfromGoldenGateBridgebetween1937and1971 D.three﹣fifthsyoungChinesewomenmaydecidetosuicidewithin2hours 3Whatshouldbethebesttitleforthetext? A.Moreliveshavebeensaved B.Suicideissurprisinglyimpulsive C.Asuicidepostponedisasuicideprevented D.Whysuicideisfallingaroundtheworld
TampaBayhasalongandcolorfulhistorywhichislocatedonthewestofFlorida.Andthereareplentyofeventsonholidayseveryyear.ThefollowingarethetopthingstoexperienceinTampaBayoverChristmas. JackieEvancho ThesuperstarexplodedontothenationalsceneafterherfirstperformanceonNBC'sAmerica'sGotTalentwhichleftaudiencesandjudgesatthetalkshowastonishedthatsuchavoicecouldcomefroma10﹣year﹣oldgirl.7:30pmRuthEckerdHall102Mullen﹣BoothRoadClearwater.﹩35～﹩65.727756﹣7400. HolidayLightsintheGardens Strollthroughthegardenswithmorethan1milliontwinklylightslasersFlorida﹣styleshowscartooncharactersvisitswithSantaandentertainersliningthepathway.5:30pmFloridaBotanicalGardens1250UlmertonRoad.LargoDonationof﹩4suggested;12andyoungerfree.727582﹣5900. RockapellaChristmas Thefive﹣manpopbandtakesonclassicholidayfavoritesongsandtheirneworiginals.7:00pmCapitolTheater.405ClevelandStClearwater.﹩25～﹩48.727791﹣7400. WordierthanThou ProseandShortStoryOpenMic:Aspecialopenmicseriesfocusingonstorytelling.Poetry诗歌andmusicalperformancesarenotallowed.Theeventincludesaperformancebyafeaturedreaderfollowedbynumerous10﹣minuteopenmicslots.7:00pmStudio@620357FirstAve.St.Petersburg.﹩5.727895﹣6620. HolidayClassicMovieSeries It'sAWonderfulLife:Enjoyselectedholidayclassicswithasing﹣alongofholidaycarolsbytheMightyWurlitzerTheatreOrganbeforeeachshow.7:30pmTampaTheater712FranklinRoadTampa.﹩10﹩8members/children.727274﹣8983. 1WhatcanwelearnaboutJackieEvancho? A.Sheisasuperfilmstar. B.Shebroadcastsnewsat7:30pmeveryday. C.Shehasaspecialtalentforspeech. D.Shebegantospeakwhenshewas10. 2Whichactivityisadmissionfreeforchildren? A.RockapellaChristmas. B.HolidayLightsintheGardens. C.WordierthanThou:ProseandShortStoryOpenMic D.HolidayClassicMovieSeries:AWonderfulLife 3Whereshouldyougoifyouareastorylover? A.Studio@620. B.RuthEckerdHall. C.CapitolTheater. D.FloridaBotanicalGardens.
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目前我国广泛种植的甘蓝型油菜AACCAC表示不同染色体组是由白菜AA2n＝20与甘蓝CC2n＝18经种间杂交染色体自然加倍形成的．科研人员利用早熟白菜A′A′2n＝20A′与A中染色体能正常配对与甘蓝型油菜为亲本培育稳定遗传的早熟甘蓝型油菜新品种主要过程如图．请回答 1甘蓝型油菜根尖分生区细胞中含有条染色体．亲代杂交时需要对甘蓝型油菜进行授粉等操作．F1杂种甘蓝型油菜的正常体细胞中含有个染色体组． 2途径1不能获得种子有人提出的解释有①F1不能产生可育的雌雄配子②F1产生的雄配子不育雌配子可育③F1产生的雄配子可育雌配子不育．结合途径2上述分析合理的是填序号． 3减数分裂时联会的染色体能正常分离不能联会的染色体则随机分配．经途径2获得的后代体细胞中染色体数介于之间其中筛选的甘蓝型油菜A′ACC细胞中来源于F1的染色体组是． 4随着生物技术的发展还可用技术培育早熟甘蓝型油菜这种育种技术的主要优点是．
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SirJamesPaulMcCartneyisanEnglishsingersongwritermulti﹣instrumentalistandcomposer作曲家.HegainedworldwidefameasthebassguitaristandsingerfortherockbandtheBeatles.Howeverit'snotjustthewordsandmusicofhissongsthatPaulusestoexpresshisfeelingsaboutthingsthatarereallyimportanttohimbuthehasalsocloselytakenpartingettingtogetheranexcitingbookforchildren. Hehasbeenworkingwithillustrator插画师GeoffDunbarandwriterPhilipArdaghtofindawaytoputwordsandpicturesintoastoryaboutanimalprotection.Theresultisastorywithanimportantmessagecontainedinabeautifulbook.Geoffdreweveryoneofthebook's84illustrationsandPhilipmadePaulandGeoff'sideascometogetherinaveryentertainingwaythatallchildrenwillenjoyreading. ThreeluckyreadersofTheNewspaperTodaywonthechancetointerviewPaulaboutHighintheClouds. OnedayinPaul'sofficeAlexMylesandJessicawastednotimeinaskingPaulGeoffandPhiliphowtheideaforthestorycameabout.Paulexplainedthathehadbeeninterestedinanimalrightsforaslongashecouldremember.SeeingtheWaltDisneyfilmofBambiwhosemotherisshotbyhuntershadabigeffectonhimasachildandmadehimthinkthathuntingwasn'tcool. Paulsaidtheydidn'twanttotellpeoplewhattodointhebook.Theyjustwantedtogetacrosstheimportanceaboutanimalprotection. 1HowdoesPaulexpresshisfeelingapartfromthewordsandmusicofhissongs? A.Bydoingwhathecantoinspirepeople. B.Bywritingabookaboutchildren. C.Byillustratinganexcitingbookaboutanimals. D.Byjoiningingettingtogetherachildren'sbook. 2Whowrotethewordsofthebookaccordingtothesecondparagraph? A.GeoffDunbar B.PhilipArdagh C.PaulMcCartney D.MylesandJessica 3WhatisHighintheClouds? A.OneofPaul'snewsongs. B.TheplacewherePaulworks. C.Abookaboutanimalprotection. D.AnarticleinTheNewspaperToday. 4Whatdoestheunderlinedphrasegetacrossprobablymean? A.make…clear. B.realize. C.ignore. D.payattentionto.
Tocommunicatewithforeignersitisimportanttoknowtheirsocialcustoms1.Oryoumayhurtthefeelingsoftheotherpartywithoutactuallyintendingtodoso.Herearesomegeneraltips. 2don'thesitatetoask.SomeJapaneseseemtofeelthatitisimpolitetoaskbackevenwhentheydon'tquiteunderstand.Howeverit'smuchbettertosaythatyoudon'tunderstandthantopretendyouunderstandandanswerveryunclearly.Whenyoudon'tunderstandyoumaysayI'mafraidIdon'tunderstandyou.Wouldyoumindsayingitagain? •Alwaysanswerwhenyouareaskedaquestion.Westernersconsideritveryrudeifaquestionisnotanswered.Theythinkitisrudetoignoreaquestion3.SomanyJapaneseonlylaughnervouslywithoutsayinganythingwhentheyarespokento.ThiscomesfromembarrassmentbutnothingismoreunpleasantforWesterners. •Speakoutwhatyouthink.Westernersexpresstheiropinionsfreely4.Theydon'tmindhearingviewsthatdifferfromtheirown.Youmayexpressfranklywhatyouthinkorfeelofcoursebutyoumustn'tberudeinyourmannerofspeech. 5.TheEnglishuseofYesandNoisthesameasinJapaneseinaffirmative肯定的questionsbutinnegativequestionstheuseisopposite.InordinaryEnglishconversationsitisusualtoaddsomethingafterthemlikeYesbyallmeans.NoIreallydon't.MayIseeit? A.Don'tanswertoosimply B.Ifyoudon't'understand C.ItisthesamewiththeJapanese D.Besuretogiveyourdifferentopinions E.ItissurprisingtofindJapanesearedifferent F.Thisisespeciallytruewhencarryingonaconversation G.Theyfeelitisnaturalforpeopletohavedifferentideas
XiaoLiacollegestudentbornafter1995usedtowashherhaireverytwodays.Butastheweatherhasgotcoldershehasbecomelazier.Shehasboughtamistspray喷雾器whichallowshertowashherhairlessoften.IwouldalsoliketohaveaproductthatcouldsavemethetroubleofputtingonmakeupshetoldOrientTodayapublicationaffiliatedtoHenanTelevision. SheisnottheonlyyoungChinesewhospendsmoneybecausesheslazy.AccordingtoareportissuedbyChina'se﹣commerceplatformTaobaoonChina'slazyeconomyChinesepeoplespent16billionyuanonproductsandservicesonlinein2018. Theso﹣calledlazyeconomyreferstoanewtypeofconsumptionofproductsandserviceswhicharedesignedtosavetimeandlabor.Accordingtothereportmanypeopleofthepost﹣1995generationbuyhigh﹣techelectronicdevicessuchasfloormoppingrobotsandautomaticwindowcleanerswhichsavethetroubleofdoinghouseholdchores.Meanwhiletake﹣outfooddeliveryservicesarealsopopularamongpeoplebomafter1995. Youngpeoplearewillingtospendmoneyonsuchproductsbecausetheywanttoenjoyhard﹣earnedleisure休闲timeafterabusyandstressfuldayatworkorschoolreportedGlobalTimes.Becausetheyneedtofocusontheirstudiesorjobstheseso﹣calledlazypeopletendtousetheirleisuretimemoreefficiently. Whilethelazyeconomymightbeconvenientforyoungpeopleitmightalsocreateproblems.The'lazyeconomy'oncampusisexpressedinthingslikepeoplebuyingfoodorotherthingswithoutleavingthedormitory宿舍.AsaresulttheystayintheirdormitoriesalldaylongplayingoncomputersandsmartphonesateachersumamedWenfromBeijingJiaotongUniversitytoldChinaNews. AccordingtoJinanDailythissituationcouldleadtoyoungpeoplebecominglesssociableandevendevelopingproblemsofcommunicatingwithothers.Youngpeopleshouldbecautiousaboutit. The'lazyeconomy'isachoiceoflifestyle.WhilethelazyeconomysavestimeandlaborthesavedtimeshouldbeusedtodovaluablethingscommentedOrientToday. 1XiaoLiismentionedto. A.introducealazygirltoreader B.explainhowyounggirlslivenowadays C.leadtothetopicofthetext D.tellusthegenerationbecomemoreandmorelazy 2What'slazyeconomy? A.Anewtypeofconsumptioncreatedbypost﹣1995generation. B.Apatternofconsumptioninwhichpeoplesavetimeandlabor. C.Anewtypeofsocietyinwhichpeoplebecomemoreandmorelazy. D.Apatternofconsumptionisdesignforthepost﹣1995generation. 3Whyyoungpeoplelikeonlineshoppingaccordingtothepassage? A.Becausethegoodsonlinearecheaper. B.Becausetherearevarietiesofgoodsonline. C.Becauseyoungpeoplewanttomakethebestofleisure休闲time. D.Becauseyoungpeoplearelazier. 4Whichisthedisadvantageoflazyeconomyaccordingtothepassage? A.Makingyoungpeoplelazy. B.Buyingunhealthyfoodonline. C.Wastingmoney. D.Makingyoungpeoplelesssociable.
如图为某植物2n＝24基因型为AaBb两对基因位于两对同源染色体上减数分裂过程中不同时期的细胞图象相关叙述正确的是
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
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. DearTerry Howareyoudoing?Inyourlastletteryouaskedmeforpart﹣timeworkinyoursummerholiday.NowIamwritingtotellyoumyopinions. Tobeginwithyoucanmakesomepocketmoneythathelpsdevelopasenseofindependent.Besidesyoucanlearnwhattodealwithvariousproblemsintheworkplace.What'smoreyoucanbuildnewfriendshipandimprovedbettersocialskills. Butasamiddleschoolstudentlearnisveryimportantforyou.Youshouldmakefulltheuseoftheholidaytostudy.Myadviceisthis:makeadetailedplanforyourstudybutworkandmanagethingsproper. Wishyouapleasantsummer. Yours LiHua
科研人员调查了白天气温与八角金盘花丛中昆虫数昆虫体温的关系结果如图．相关叙述正确的是
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
假如你是李华今年暑假你将去英国CliftonSchool学习一个月并将寄宿在英国学生Jack家中.写一封电子邮件向他介绍自己并询问几个问题1.住宿方式2.能否上网3.饮食方式4.到校的交通 注意:1.词数100左右可适当增加内容2.开头和结尾已给出不计入总词数 DearJack IamLiHuaahighschoolstudentfromChina.……… Yours LiHua
我国是一个严重缺水的国家大家应倍加珍惜水资源节约用水．据测试没拧紧的水龙头每秒钟会滴下2滴水每滴水约0.05毫升．小明同学在洗手后没有把水龙头拧紧当小明离开4小时后水龙头滴了多少毫升水结果用科学记数法表示
棉花栽培中适时打顶去顶芽是棉花高产栽培的关键技术之一．打顶解除了顶端优势会改变棉株的生长中心影响植株体内光合产物和矿质养分的分配但打顶后棉株叶片在花铃后期出现早衰现象．科研人员研究了打顶后涂抹NAA对长绒棉结铃和产量的影响结果如表．请回答 注N0打顶后立即将空白羊毛脂放在切口N1打顶后立即将含浓度为3×10﹣3mmol•L﹣1NAA的羊毛脂放在切口N2打顶后立即将含浓度为3×10﹣2mmol•L﹣1NAA的羊毛脂放在切口． 1顶端优势体现了生长素生理作用具有． 2处理②和③的实验结果相差不大说明．处理④棉株的单株产量较高的原因是外源适宜浓度的NAA能提高结铃数和成铃率． 3打顶后涂抹一定浓度的NAA既保证了打顶后棉株体内的合理的生长素水平有利于更多的光合产物分配到器官又可避免因不打顶使棉株具有旺盛的顶端生长优势从而使养分过多消耗在器官上． 4为探究打顶后棉叶出现早衰现象的原因科研人员在花铃后期检测了处理①②④组的棉株叶片内相关植物激素的含量变化结果如图．据图分析叶片出现早衰现象的原因是同时说明植物生命活动是多种激素的结果． 5综合研究结果对棉花生产的指导意义是．
TwoyearsagoattheBritishAcademyofFilmandTelevisionArtsteapartyinLosAngelesMillieBobbyBrownwasacharmingdarling.WhenevershemetsomeoneshewouldextendherhandandsayHi!I'mMillieBobbyBrown.Sogladtomeetyou! BestknownforstarringasElevenayounggirlwithpsychokineticabilitiesinthehitsci﹣fiTVseriesStrangerThingsBrownisaniconforhergenerationasWmagazineputit. ToplayElevenBrownhadtocutoffherlonghairandshaveherheadwhichissomethingthatwouldbequitedifficultforanyteenager.ButtheBritishactressdiditwithoutasecondthought.Thisisperhapswhatsetsherapartfromfellowchildstars.Ontheonehanditwascool.Whenyou'rebaldrainfeelslikeaheadmassage.I'dwalkintherainandpeoplewouldlookatmelikeIwascrazyshetoldWButontheotherhandpeoplestaredatmewonderingwhetherIwassick.SomewouldevenlaughatmewithoutknowingwhetherIwasorwasn'tsick. ThesepeoplecertainlyhurtBrownesfeelingsbuttheyalsotaughthersomethingaboutcompassion.IntheendbeingbaldwasthebestthingIeverdid﹣beingdifferentchangedmylife.Iwantedtoembracemybaldnessandhopefullyinspirepeopleshesaid. HerbraverywonherthehonoroftheyoungestUNICEFGoodwillAmbassadorlastmonth. It'sahugehonortobecomeUNICEF'snewestandyoungesteverGoodwillAmbassadorthe14﹣year﹣oldwhohassupportedthechildren'scharitysince2016wroteonsocialmediaplatformInstagram.IamlookingforwardtomeetingasmanychildrenandyoungpeopleasIcanhearingtheirstoriesandspeakingoutontheirbehalf. ChildrenaretheirownbestadvocatesHenriettaForeUNICEF'sexecutivedirectorsaidinanannouncement.IknowthatMilliewilluseherpassiontodefendtherightsofvulnerablechildrenandyoungpeopleeverywhere. 1FromthepassageweknowthatMillieis. A.conservative B.aggressive C.outgoing D.energetic 2WhatdidMilliedotoplaywellinStrangerThings? A.Shetiedupherlonghair. B.Shemadeherheadbald. C.Shelearnedfromotherfellowstars. D.Sheshavedherbody. 3WhichstatementisTRUEaccordingthepassage? A.Milliewasgreatlyencouragedbyothers. B.Milliedidn'tregrettedbeingshaved. C.Milliewasinspiredbyallkindsofcomments. D.Milliewasdiscouragedbymisunderstanding. 4What'sHenriettaFore'sopinionaccordingtothepassage? A.Millieissuretohelpthevulnerablechildrenaroundtheworld. B.ChildrenareMollie'sbestadvocates. C.Milliewilldoherbesttodefendagainstvulnerablechildren. D.Therearesomanyvulnerablechildrenandyoungpeopleintheworld.
把下列数据用科学记数法表示出来地球离太阳约有1亿5千万千米
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