首页
试卷库
试题库
当前位置：
X题卡
>
所有题目
>
题目详情
写出下列各数的相反数：-2
查看本题答案
包含此试题的试卷
教案备课库《》真题及答案
点击查看
你可能感兴趣的试题
分别写出下列各数的相反数-10．
分别写出下列各数的相反数-3
写出下列各数的相反数并画出数轴在数轴上表示这些数和它们的相反数然后用＜连接 ﹣2.51﹣1.50
分别写出下列各数的相反数3．
写出下列数的相反数﹣302﹣5画出数轴并把下列各数的相反数在数轴上表示出来．
分别写出下列各数的相反数-8
写出下列各数的相反数-7.5
分别写出下列各数的相反数-2.5
分别写出下列各数的相反数1
写出下列各数的相反数0
分别写出下列各数的相反数+4
写出下列各数的相反数2
写出下列各数的相反数并画出数轴在数轴上表示这些数和它们的相反数然后用＜连接 ﹣2.51﹣1.50
分别写出下列各数的相反数0．
已知下列各数40－2－.1用
分别写出下列各数的相反数.5-7-3+11.20.
写出下列各数的相反数9
写出下列数的相反数并在数轴上表示下列各数及其相反数+2.50+1﹣3.5．
写出下列各数的相反数-3.5
.写出下列各数的相反数并把所有的数包括相反数在数轴上表示出来.4+﹣4.50﹣+3
热门试题
更多
在元素周期表中元素AB位于同周期A在ⅡA族B在ⅢA族．A的原子序数为aB的原子序数为b不可能是
两种气态烃组成的混合气体0.1mol完全燃烧得0.16molCO2和3.6g水下列说法正确的是
下列说法中肯定错误的是
Ofthethreemajordrinksoftheworld﹣teacoffeeandcocoa﹣teaisconsumedbythe1largenumberofpeople. Chinaisthehomelandoftea.Humancultivationofteaplantsdatesbacktotwothousandyearsago.TeafromChinaalong2hersilkandporcelainbegantobeknowntotheworldmorethanathousandyearsagoandsincethenit3beanimportantChineseexport. AtpresentmorethanfortycountriesintheworldgrowteawithAsiancountries4produce90%oftheworld'stotaloutput.AllteatreesinothercountrieshavetheirorigindirectlyorindirectlyinChina.Thewordfortealeavesorteaas5drinkinmanycountriesarederivatives衍生物fromtheChinesecharactercha.TheRussianscallitcha'i6soundslikechayetealeavesasitispronouncedinnorthernChinaandtheEnglishwordteasoundssimilartothepronunciationof7itcounterpart对应物inXiamen.TheJapanesecharacterforteaiswritten8exactthesameasitisinChinesethough9pronouncewithaslightdifference.ThehabitofteadrinkingspreadtoJapaninthe6thcenturybutitwasnotintroducedtoEuropeandAmericatillthe17thand18thcenturies.Nowthenumberoftea10drinkintheworldisstillontheincrease.
原电池的电极名称不仅与电极材料的性质有关也与电解质溶液有关．下列说法中不正确的是
在一定温度下容器内某一反应中MN的物质的量随反应时间变化的曲线如图下列表述中正确的是
下列说法正确的是
WhenIwasyoungeachmorningIwokeupandwouldfindmyfathernowherearoundthehouse.Heusuallygotupearlybefore1andbeganmilkingthecowandcleaningthefarmyard.Insummerhegotup2earliertomopthegrassandwatertheflowersandvegetablesinthegarden.OnceIhelpedmyfatherto3weeds杂草fromthecornfield.Itwaslong4Ifeltverytiredbutthefieldridge田垄seemed5.FinallyItotallythrewmyself6inthefieldfeeling7.Mydadseemedtohave8mymind.HecameupandsaidFarmingisbackbreakingandreallytakes9andsweatbutin10thesweetharvestwillbeworththe11.EncouragedbyhiswordsIstruggledtomyfeet.Myfather12andaddedRomeisnotbuiltina13butitcanbebuiltinhundredsofdays.Sowhenever14withahugeprojectjustbreakitinto15partsandthencompleteitonebyone.Finallyyouwillbeamazedatyour16.HearingwhathesaidIwasgreatly17andcontinuedremovingtheweedsfrompatchtopatch.BelieveitornotattheendofthedayI18inweedinghalfanacreofcornfield. NowIhavetrieddifferentjobsandfinally19downabigrestaurant.Inmylifetimemyfather'sdevotiontohisjobandhisspecialworkingmethodscanalwaysencourageandguideme20allkindsofdifficulties. 1A.dark B.dawn C.noon D.midnight 2A.less B.equally C.even D.extremely 3A.forbid B.throw C.drop D.remove 4A.before B.whenever C.since D.until 5A.changeable B.endless C.faraway D.boring 6A.open B.flat C.away D.aside 7A.angry B.disappointed C.hopeless D.embarrassed 8A.read B.disturbed C.spoken D.seen 9A.pains B.time C.courage D.patience 10A.winter B.spring C.summer D.fall 11A.strength B.effort C.cost D.risk 12A.smiled B.regretted C.sighed D.followed 13A.second B.month C.day D.year 14A.faced B.discouraged C.dealt D.worked 15A.good B.various C.small D.large 16A.result B.achievement C.failure D.change 17A.inspired B.shocked C.delighted D.puzzled 18A.managed B.failed C.succeeded D.avoided 19A.settled B.broke C.bent D.pulled 20A.around B.to C.with D.through
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.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. DearMary I'mpleasingthatyouwillcometoChinatostudythelanguageandculture.LivinginChinamightseemalittlestrangeatfirstsoI'msureyou'llsoonlikeit. Chinesepeopleisveryfriendlyandeasygoingsoifyouaresociableitwillbeeasilyforyoutogetusedtothelifehere.I'llintroduceyoumyfamilyandfriendandyouwon'tfeellonelyI'msure.Besideit'llhelpmetolearnChineseandChineseculture. InthewordI'lltrymybesttomakeyoufeelatmyhomeandI'mlookingforwardtomeetingyou. Yours John.
Momwantedonlyonethingforherbirthday.Canyoufindmeanothercopyofthissong?sheaskedandhandedmeaworn﹣outcassettetape.IknewexactlywhatwasrecordedonitMyRedeemer救世主.Iheardthesongplayedatleastathousandtimeswhilegrowingup.Aftersomanyyearsthecassettetapewastoowornouttobeused.IpromisedherIwouldfindareplacement. MyRedeemerbecameMom'sfavoritesongaftermyyoungerbrotherTimwaskilledbyadrunkdriverin1973.TheonlythingthathelpedhercalmdownwasthesoulfulsoundofMyRedeemerfromthelocalradiostation. Werecordeditonacassettetapesoshecouldlistentoitanytimeshewantedbutnoneofusknewwhothesoloist独唱者was.ThesedaysIthoughtthesongwouldbeeasytofindout.IwenthomeandsearchedtheInternet.SeveralsongswiththattitlepoppedupbutnoneofthemwastheoneMomloved.Igotfrustrated. Mom'sbirthdaydrewnearandthenonedayIwasdrivinghomelisteningtoourlocalradiostation.Afamiliartunecameon.ItwasMyRedeemer!AssoonasIcouldIphonedthestation.IgotalineonthesoloistwhowascalledAlanParks.ItypedhisnameintoGoogleandfoundhishomenumberinSouthCarolina.MinuteslaterIwastellinghimhowmuchhisrecordingmeanttoMom.HeofferedtoshiptwoCDsouttomepersonally.Igavehimmyaddress. RedLionPennsylvania?hesaid.DoyouknowtheLogans?Theyareourneighbors!I'vebeenfriendswiththemfor25yearsAlansaid.They'llbeatmyconcertatYorkGospelChapelonApril17th.Wouldyouandyourmomcometoo?Wesurewould.MomwasexcitedtohearAlansingMyRedeemertoherliveinconcert﹣ontheeveningofher87thbirthday. 24.WhywasthesongMyRedeemersoimportanttotheauthor'smother? A.Itcouldcomforthersadandpainfulmood. B.Itremindedherofthelovefromherhusband. C.Itwasgiventoherbyaveryimportantfriend. D.Itwastheonlythingthattheauthor'sbrotherlefther. 25.WhatdoestheunderlinedpartgotalineoninParagraph3mean? A.Talkedhappilywith. B.Thoughtalotabout. C.Maderequestof. D.Gotinformationabout. 26.WhatcanwelearnaboutAlanParksfromthispassage? A.HelivedinRedLionPennsylvania. B.Heisakindandwarm﹣heartedmusician. C.Heofferedtogivetheauthortwocassettetapes. D.Hewouldsingfortheauthor'smomontheradiostation. 27.Whichofthefollowingismostsurprising? A.AlanParksandtheauthorlivedinthesameneighborhood. B.AlanParkshappenedtogettoknowtheauthor'smother. C.Theauthor'smotherwenttotheconcertonherbirthday. D.Theauthor'smotherbecamegoodfriendswithAlanParks.
若是烯烃与H2加成后的产物则烯烃可能有的结构有
某同学现要用图甲所示的电路原理图来测定一节电池的电动势和内电阻．图中R0两端的对应电压U．实验时通过改变电阻箱的阻值从而得到R0两端的不同电压实验中记录下不同的电阻R的阻值和本次实验中电压表的读数．实验后已将实验数据描在了图乙所示的﹣R+r坐标系中．已知R0＝150Ω请完成以下数据分析和处理． 1请根据原理图将图丙中的实物图连接好． 2在图乙中画出﹣R+r关系图线 3由此可得电池电动势E0＝V．结果保留两位有效数字
假如你是李华你的英国朋友Edward正在学习汉语希望你推荐一个适合他学习汉语的网站.请你根据以下内容给他回复邮件. 推荐网站www.edchinese.com 网站内容 1.网络课程中文情景对话中国风俗成语 2.其它中文电影中文歌曲唐诗等 3.有在线教师答疑解惑. 费用全部免费 注意1.词数100左右 2.可以适当增加细节以使行文连贯. .
Asimplegesturecanbeformedintoachild'smemorysoquicklythatitwillcausethechildtogiveafalseanswertoaquestionaccompaniedbythatgesture.Anewfindingsuggeststhatparentssocialworkerspsychologistsandlawyersshouldbecarefulwiththeirhandsaswellastheirwords. WhilememoriesofbothadultsandchildrenareeasytoreacttosuggestionthoseofchildrenareknowntobeparticularlyinfluencedsaidleadresearcherSaraBroadersofNorthwesternUniversity.Kidsareusedtolookingtoadultstotelleventsforthemandcanbemisledevenifnotintentionally. Previousresearchforexamplehasshownthatdetail﹣loadedquestionsoftencausefalseanswerswhenaskedsayDidyoudrinkjuiceatthepicnic?thechildislikelytosayyesevenifnojuicehadbeenavailable.Itisnotthatthechildisconsciouslylyingbutratherthedetailisquicklyformedintohisorhermemory. Toavoidthisproblemsocialworkershavelongbeenadvisedtoaskchildrenonlyopen﹣endedquestionssuchasWhatdidyouhaveatthepicnic?Butanopen﹣endedquestionpairedwithagesturebrieflymeaningajuiceboxistreatedlikeadetailedquestion.Thatischildrenbecomelikelytoanswerfalsely. Anditisn'tjustafewkids77%ofchildrengaveatleastonepieceoffalseinformationwhenadetailwassuggestedbyanordinarygesture.Gesturesmayalsobecomemorepopularwhentalkingwithnon﹣fluentlanguageuserssuchaslittlekidsBroaderssaidashandmovementscanimpartmeaningofunfamiliarwordsandphrases.Itcertainlyseemsreasonablethatadultswouldgesturemorewithchildren. IngeneralBroadersadvisesparentsandotheradultstotrytobeawareofyourhandswhenquestioningachildaboutanevent.Otherwiseyoumightbegettinganswersthatdon'treflectwhatactuallyhappened. 32.Accordingtothetextgestures. A.havenotanyfunctionatall B.arerarelyusedbypeople C.havecertaineffectonchildren D.areoftenusedbysocialworkers 33.WhyarekidseasytobemisledbygesturesaccordingtoSaraBroaders? A.Thesegesturesareveryattractive. B.Theirmemoriesareaffectedeasily. C.Childrenareeasytotelllies. D.thesegesturesareusedfrequently. 34.Accordingtothetextwhichofthefollowingquestionsmaycauseawrongreply? A.Whatwillyouhaveforlunch? B.DidyoucheatinthelastEnglishexamination? C.WhereareyougoingLucy? D.Didyouseeanythingelselastnight? 35.TheunderlinedwordimpartinParagraph6means. A.separate B.tellapart C.confuse D.passon.
如图1所示水平面上固定一倾角为α＝30°的光滑斜面斜面的底边与顶边PQ平行在斜面上有一虚线MNMN∥PQ在MN与PQ之间存在垂直斜面向上的磁场已知磁场的磁感应强度B随时间的变化规律如图2所示将矩形导线框ABCD放在斜面上且AB∥PQ从t＝0时刻起对线框施加一沿斜面向上的恒力F使线框由静止开始运动当线框到达MN时开始匀速进入磁场．已知线框的质量m＝1kg电阻R＝0.2ΩAB边长为x1＝1mBC边长为x2＝0.4mMN与PQ间的距离足够大F＝10Ng＝10m/s2．求 1矩形线框到达MN前的加速度以及在磁场中匀速运动时的速度 20﹣2.1s内矩形线框产生的焦耳热．
将过量的两份锌粉ab中分别加入少量且等量的稀硫酸溶液中同时向a中加入少量的CuSO4溶液下列各图表示的是产生H2的体积V与时间t的关系其中正确的是
一同学要测水的折射率他找来一个方形容器装满水测得容器深度为h容器宽度为L他将此容器装满水紧贴容器竖直立一细杆并在细杆上系一红布条调整布条高度当在对面观察布条在水中的倒影与容器底部A点重合测出此时布条到容器上边界的高度H如图所示请你帮助该同学推导出水的折射率表达式．
EveryFebruary14peopleworldwidedemonstratetheiraffectionforfamilymembersfriendsteachersandsignificantotherswithagiftortwo.Howeverthisdisplayoflovedoesnotcomecheap.55%ofAmericanscelebrateValentine'sDayin2017byspendinganaverageof136.57dollarseach.Itisnowonderthatretailers零售商lovetheholiday. In1861RichardCadburyamanfromaBritishchocolatecompanycameupwiththeideaofpackagingchocolatesinheart﹣shapedboxesforValentine'sDay.Notsurprisinglytheywereaninstantsuccessandatraditionwasborn.TodayAmericansspendoveronebilliondollarshandingoutboxesofchocolatestotheirlovedones.Sweetheartstheheart﹣shapedcandyarealsoverypopular.Accordingtothemanufactureramajorityofthe8billionpiecesofcandymadeannuallyaresoldbetweenJanuary1andFebruary14. MassachusettsbusinesswomanEstherHowlandpopularizedValentine'sDaygreetingcardsinAmerica.OftencalledTheMotheroftheAmericanValentinetheartistwasthefirsttosellhandmadepapercardswithmessagesoflovetoretailers.Withover145millioncardsboughtintheUSandoverabillionworldwideValentine'sDayisnowoneofthebiggestbusinesschancesforgreetingcardcompanies.ItisnowonderthatthedayisoftenreferredtoasaHallmarkHoliday. Flowersarealsoverypopular.About51%ofpeoplemainlymenbuyredrosesfortheirlovedones.GiventhatValentine'sDayisverypopularforweddingproposals求婚itshouldnotcomeasasurprisethatalotofthemoneyspentonthisdayisusedtobuyfinejewelry.WithaquarterofAmericanstreatingtheirlovedonestoaromanticmealthedayisalsomuchwelcomedbyrestaurantowners. PopeGelasiusthemanwhomadeFebruary14Valentine'sDayin496ADwouldhaveneverimaginedthatthisfestivalwouldchangeintosuchanexpensivecelebration! 32.Whatdoesthefirstparagraphmainlytellus? A.PeoplebuytheirfriendsgiftsonFebruary14. B.Valentine'sDayiscelebratedeveryyear. C.Valentine'sDayisagoodtimetoshowlove. D.AlotofmoneyisspentonValentine'sDay. 33.WhichistrueaboutRichardCadbury'sidea? A.Itresultedinanewtasteofchocolate. B.Itledtothebirthofanewtradition. C.ItwasputforwardonValentine'sDay. D.Ithelpedthecompanyearnonebilliondollars. 34.Valentine'sDayisreferredtoHallmarkDaybecause. A.peoplegetgreetingcardsonthatday B.itwaspopularizedbyMissHowland C.itofferscardscompaniesbigbusinesschances D.retailshelpsendmessagesofloveonthatday 35.Whatisprobablyanecessarygiftforaweddingproposalaccordingtothepassage? A.Heart﹣shapedcandy. B.Messagesoflove. C.Aromanticmeal. D.Apieceofjewelry.
如图所示某厂生产的压力罐容积为100L27℃时内部密闭了1atm的空气．现用水泵给压力罐注入27℃的水使注水后罐内的压力变为3atm 1设注水过程中封闭空气的质量和温度都不变求注入水的体积 2实际上在注水过程中内部空气的温度略有升高请说明温度略有升高的原因．
已知H++OH﹣＝H2O生成1molH2O放出热量57.3kJ下列反应中放出57.3kJ热量的是
Most7﹣year﹣oldgirlsareplayingBarbieandjumpingrope.ThoughSailorGutzlermayhaveenjoyedthose41shewasalsoanactiveparticipantin42activitieswithherfather.Hewasapilotandhetaughther43skills.Sheactuallyusedthese44whenherfamily'stwin﹣engineplane45upsidedowninruralKentucky.They'dbeentraveling46toIllinoisincoldweatherfromaChristmasvacationinKeyWestFlorida. Sailorhadbrokenbonesbutwhenshecouldn't47herfathermothersisterorcousinafterthecrashshe48herselffromtheremainslitastickontheburningwingoftheplaneandwalked49foramilethroughthecolddarknessofthewoodedKentucky50. Sailor51thenearesthousehopingtogethelpforher52.Shetoldthewomanwhoansweredthe53thatshe'dbeeninan54andthatherparentsweredead. Thoughthetemperaturewas5℃belowzeroSailorwaswearingclothingmeantforthe 55Floridaandonlyhadononesock.56she'sasurvivor. Thoughherfatherhadbeen57sincehewas16andwasaflight58formorethan4000hoursdisasterstillstruck.Hehadmadethesameexact59manytimesbutstilltheweatherwon.60he'dtaughthisdaughterwhattodoandshedidit. 41.A.ropes B.sports C.activities D.dolls 42.A.outdoor B.social C.school D.daily 43.A.repair B.flight C.communication D.survival 44.A.skills B.tricks C.thoughts D.activities 45.A.flew B.landed C.swung D.appeared 46.A.around B.home C.abroad D.everywhere 47.A.wakeup B.strugglefor C.calloutto D.getcontactwith 48.A.hid B.supported C.pulled D.protected 49.A.fast B.steadily C.heavily D.endlessly 50.A.countryside B.tunnel C.wonderland D.desert 51.A.gotreadyfor B.wentonfor C.madeitto D.lookedforwardto 52.A.fear B.loss C.plane D.family 53.A.question B.request C.girl D.door 54.A.crash B.attack C.holiday D.dilemma 55.A.remote B.warm C.rainy D.famous 56.A.Actually B.Besides C.Finally D.Still 57.A.practicing B.flying C.studying D.fighting 58.A.agent B.planner C.steward D.instructor 59.A.decision B.trip C.mistake D.plan 60.A.Previously B.Accidentally C.Fortunately D.Amazingly
Forfamiliesonvacationaplaygroundprovidesawelcomebreak.Itcanalsoprovideaglimpseintothelocalculturefromthesetupoftheparktothewaysfamiliesinteract.Herearethedesignsthatliveuptothatchallenge. FruitandScentPlaygroundStockholm Isthereapickyeateronasteadydietofchickenfingersandcheese?PerhapsatriptoSweden'sFruitandScentPlaygroundwillchangehisorherculinary烹饪的tune.ThisplaygroundfeaturesabananaslideanorangeseesawpearhutsawatermelonjunglegymandapairofcherryswingsalldesignedbypublicartistJohanFernerStrom.Nowwhocansayyoucan'tplaywithyourfood? NishiRokugoParkTokyo LocatedbetweencentralTokyoandthecityofKawasakiNishiRokugocombinesrecycledrubbertires橡胶轮胎withtraditionalplaygroundequipment.Intotalmorethan3000tiresofdifferentsizesareusedtocreatetunnelsbridgestallsculpturesforclimbingandofcoursetireswings.There'slittleshadesoyoucanvisithereintheearlymorningorlateafternoonforthemostcomfortableweatherandbesuretowearyourplayclothes. BicentennialChildren'sParkSantiagoChile BicentennialChildren'splaygroundinMetropolitanParkwasbuilttocelebrate200yearsofChileanindependenceandimprovethelivesofSantiagocitizens.Dozensofslidesarebuiltintotheslopecreatingadesigncompletelycomplementary互为补充的ofthesurroundinglandscape.Fountainsoffersomerelieffromthesunandampleseatinggivesparentsaplacetorelax. 1WhatcanbelearnedaboutFruitandScentPlayground? A.ItislocatedinTokyoJapan. B.Itsdesignwasledbysomeartists. C.Itisaimedatbalancingpeople'sdiet. D.Itsfacilitiesaremodeledafterfruits. 2WhenvisitingNishiRokugoParkitisbetterto. A.wearthickprotectiveclothes B.avoidmomentswhenit'shot C.takeumbrellasandraincoats D.watchoutfortheequipment 3WhydoestheauthorrecommendBicentennialChildren'sPark? A.Itbecomespartofthesurroundings. B.Itwasbuilttoimprovepeople'slives. C.Itamuseskidsandhelpsparentsgetrelaxed. D.Itprovidesslidesforbothchildrenandadults.
2SO2g+O2g2SO3g是制备硫酸的重要反应．下列叙述正确的是
Idon'twantkids.IknowIwouldn'tmakeforaverygoodmother.It'snotthatI'ddropthemorforgetthematthegrocerystoreoranythinglikethatbutthey'renotagoodfitformeandthelifeI'vecreatedformyself.I'dratherbeinCambodiakissingelephantsorcagedivingwithsharksinCapeTownorwanderingthestreetsofParisacitythathasbecomemysecondhomethantrappedathomedoingthemomthing. Theitchtobecomeamotherisn'tinmebuttheitchtotravelandtravelfarandoftenis. Iftheurgeisn'tthereIdon'tthinkit'sfairtolivealifeIdon'twantandhaveababybecausesomeoneelsethinksIshould.Thatwouldbeawful. Ilikechildren.TosayIlovethemwouldn'tbecompletelyaccurate.It'snotbecauseI'mamonster﹣thesamemonsterpeoplewhofeelwomenshouldhavechildrenwillcallme﹣butIsimplydon'tlovethembecauseI'mnotaroundthemmuch.VeryfewofmyfriendshavechildrenandtheoneswhodoIdon'tseemuchbecausewelltheyhavechildren. IhavetwonephewsinColoradowhomIlovetopiecesbutIdon'tseethemveryoften.Idon'tgooutthereasoftenasIprobablyshouldbecauseI'dratherbetraveling.SomepeoplemaycallthisselfishbutIcallitlivingmybestlife. WhenItalktomysisteraboutmynephewseverythingtheydoandsayisexcitingtoher.ThejoymysisterfeelsbyjustplayingwiththemintheyardisthesamejoyIfeeleverytimeIgetoffaplaneinanewcountry.I'dratherbeonthebeachesofSpaineverysummerwhileshepreferstospendherdaysathomewiththemclimbingtreesandsuch.I'mfulfilledonewaywhileshe'sfulfilledanotherway. I'mverymuchcertainthatatthispointinmylifemygreatestfulfillmentcomesintheformoftravelingandbeingfreeofkids.IcangoanywhereatanytimeIdon'thavetoputmylifeonholdforsomeoneelse.It'scompleteandtotalfreedom. 24.WhatdoestheunderlinedworditchinParagraphTwomean? A.traditionB.competenceC.planD.desire 25.Whyistheauthorregardedasamonster? A.Becauseshedoesn'tlikekids. B.Becauseshedoesn'twantchildren. C.Becauseshe'sdifferentfromherfriends. D.Becausesherarelystayswithchildren. 26.Whichislivingmybestlifeaccordingtotheauthor? A.Tostaywithherfamily. B.Toseehernephewsoften. C.Tovisitanewcountry. D.Totalkwithhersister. 27.Whatistheauthor'spurposeofwritingthepassage? A.Toexplainherchoiceoflife. B.Topersuadepeopletotravel. C.Toshareherhappinessinlife. D.Tointroduceauniquelifestyle.
Youcantellalotaboutpeoplebylookingattheirhair﹣notjustwhethertheybrushsprayorblow﹣dry.Scientistshavefoundawaytousehairtofigureoutwhereapersonisfromandwherethatpersonhasbeen.Thefindingcouldhelpsolvecrimesamongotherusefulapplications. Wateriscentraltothenewtechnique.Theliquidmakesupmorethanhalfanadulthuman'sbodyweight.Ourbodiesbreakwaterdownintohydrogen氢andoxygen.Atomsofthesetwoelementsendupinourtissuesfingernailsandhair. Butnotallwateristhesame.Hydrogenandoxygenatomscanvaryinhowmuchtheyweigh.Inthecaseofhydrogenforexampletherearethreetypesaccordingtotheirweights.Eachtypeiscalledahydrogenisotope同位素.Anddependingonwhereyoulivetapwatercontainsdifferentisotopes. Canhairrecordthisinformation?That'swhatJamesR.EhleringeranenvironmentalchemistattheUniversityofUtahwondered.Tofinditoutheandhiscolleaguescollectedhairfromhairstylistsin65citiesacrosstheUnitedStates.Eventhoughpeopledrinkalotofbottledwaterthesedaystheresearchershavefoundthatpeople'shairhasthesameisotopesasfoundinlocaltapwater.That'sprobablybecausepeopleusuallycooktheirfoodwiththelocalwater. Authoritiescannowusetheinformationtoanalyzehairsamplesfromcriminalsorcrimevictimsandnarrowtheirsearchforclues.ForexampleonehairsampleusedinEhleringer'sstudycamefromamanwhohadmovedfromSanFranciscotoSaltLakeCity.Ashishairgrewitreflectedhischangeinlocation. 1WhatdoweknowaboutthehydrogenisotopesaccordingtoParagraph3? A.Theyareclassifiedbysize. B.Eachtypeofthemdiffersinweight. C.Theycanimprovethequalityoftapwater. D.Someofthemcannotcombinewithoxygen. 2Whyisitpossibletoknowwherepeoplearefrombyanalyzingtheirhair? A.Peopleusethesamebottledwater. B.Peoplewashtheirhairindifferentways. C.People'shairisaffectedbytheweatheroftheplacestheystay. D.People'hairindicatesthetypeofwaterintheplacestheystay. 3Thelastparagraphismainlytoshow. A.howtorecognizecriminals B.howtocollecthairsamples C.theusefulnessofhairanalysis D.theprocessofEhleringer'sstudy 4Whichofthefollowingcanbethebesttitleforthepassage? A.Watercomposition B.Changeyourhair C.Hairdetectives D.Nowayout
将三个可以视为质点的物块ABC放在光滑的水平面上将一轻弹簧与物块B相连接右端与物块C接触但不连接开始整个系统处于静止状态今给物块A一向右的速度v0＝3m/s经过一段时间A与B发生碰撞碰后AB粘合在一起然后通过弹簧的作用使物块C也发生运动且最终物块C脱离弹簧已知mA＝1kgmB＝2kgmC＝3kg．求 ①整个运动过程中弹簧储存的弹性势能的最大值 ②物块ABC的最终速度．
下列每组中各物质内既有离子键又有共价键的一组是
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. Ms.Trumpismyhistoryteacher.Shelovesasubjectthatsheteachesandhasacompletelyknowledgeofittoo.Historycomesaliveinhisclasswherenoonetalksaboutsomethingbutthetopic.Shelikestoteachbytellingstorieswhatalwaysmakesherlessonssointerestingbuteasytounderstand.Ms.Trumpalsohasagoodknowledgeofothersubjectandoftenlinksittowhatsheteachesabout.Thebestpartaboutheristhatshe'salwaysnicetothosestudentswhoneedsmoretimetograspthesubjectencouragingthemaskquestionssothattheycanunderstandthesubjectbetter.
100mL浓度为2mol•L﹣1的盐酸跟过量的锌片反应为加快反应速率又基本不影响生成氢气的总量可采用的方法是
HowtoManageYourPhone'sDataUse Smartphonesgiveyouaccesstoawealthofinformationandmediabutmostnetworksputalimitontheamountofdatayoucanuseeachmonth.Atypicalphonecontractincludesadataallowanceofbetween500MBand10GBpermonth.1Youseeyourusagecanmountupsurprisinglyquickly﹣watchingafilmonthephoneisabout700MBinSDanhourofstreamingTVisaround500MBor60﹣140MBforthesameofradiochattingonSkypeforanhourisaround40MB.2 •IfpossiblewaituntilyoucanconnecttofreeWi﹣Fibeforeusingyourphone'sdatafeatures. •Whenyouareontheroaduseyourcar'sGPSnotyourphonetofindtheway.3ButmapsarepreloadedinaGPSmakingthisfreetouse. •4Manyofthesearefundedbyadsthatpopuponyourscreen.Everyadhastodownloadthroughyournetworkusingupyourdataallowance. •Ifyouregularlyneedtousealotofdataonyourphoneconsideradata﹣compressing压缩appsuchasOnavowww.onavo.com.5Soyouuselessofyourmonthlyallowance.Youmayhavetosubscribetosuchcompressionservicessoyou'llneedtoweighupwhetherit'sworththecost. A.Themoredatathehigherthemonthlycost. B.RemembertousefreeWi﹣Fianywhereyougo. C.Trythesetipstobettermanageyourdatause. D.Itcompressesdatabeforeitisfedtoyourphone. E.Butyoumightenduppayingmorethanexpected. F.Thephonehastodownloadmapdataasyoumove. G.Becarefulofhowmanyfreegamesyouplayonthephone.
热门题库
更多
教案备课库
教案备课库
教案备课库
高一下学期数学
教案备课库
高一上学期数学
高一上学期化学
教案备课库
教案备课库
教案备课库
高一上学期物理
教案备课库
教案备课库
教案备课库
教案备课库
教案备课库
湘公网安备 43130202000226号