首页
试卷库
试题库
当前位置：
X题卡
>
所有题目
>
题目详情
二次根式有意义时，x的取值范围是（ ）
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
使二次根式有意义的x的取值范围是
若二次根式有意义则x的取值范围是____________.
要使二次根式有意义则x的取值范围是_____.
若二次根式有意义则x的取值范围是____.
二次根式在实数范围内有意义则x的取值范围为
要使二次根式有意义则x的取值范围是_______.
若二次根式有意义则x的取值范围是.
如果二次根式有意义那么x的取值范围是.
若二次根式在实数范围内有意义则x的取值范围是
若二次根式有意义则X.的取值范围是.
若二次根式有意义则x的取值范围是
x<2
x≠2
x≤2
x≥2
使二次根式有意义的x的取值范围是.
使二次根式有意义的x的取值范围是
若二次根式有意义则X.的取值范围是.
使二次根式有意义的x的取值范围是.
要使二次根式有意义则x的取值范围是__________.
要使二次根式有意义则x的取值范围是_______________.
二次根式有意义则x的取值范围_______
若二次根式有意义则x的取值范围是__.
要使二次根式有意义则x的取值范围是__________.
热门试题
更多
在平面直角坐标系中点O为坐标原点点P﹣2aQ﹣2a﹣5若△POQ是直角三角形则点P的坐标不可能为
当抛物线y＝ax2+bx+cabc为常数c≠0与x轴交于AB两点时以AB为边作矩形ABCD使点C点D落在直线y＝c上我们把这样的矩形ABCD叫做该抛物线的“伴随矩形”． 1①抛物线y＝x2﹣2x﹣2的“伴随矩形”的长为 ②当抛物线y＝x2﹣2x+cc为常数存在“伴随矩形”c的取值范围是 2已知抛物线y＝ax2+bx+3经点20当该抛物线的“伴随矩形”是正方形时求出该抛物线所对应的函数表达式 3对于函数y＝ax2﹣2x+2aa为常数 ①当该函数的图象与x轴只有一个交点时求出交点的坐标 ②我们把平面直角坐标系中横纵坐标都为整数的点称为“好点”当抛物线y＝ax2﹣2x+2aa为常数a＞0的“伴随矩形”内部包括矩形边界恰有6个“好点”时直接写出a的取值范围．
每年4月23日是世界读书日.假定你是李华你的英国朋友David来信询问你校读书日的相关活动请给他写一封回信.内容包括: 1.本次读书日的主题:诵读经典名著传承中华文化; 2.简要介绍你校读书日的活动安排; 3.本次活动的意义. 注意: 1.词数100左右 2.可适增加细节以使行文连贯 参考词汇:经典名著classics
TheSpanishpeoplehavetheirowndiningschedulewhichisverydifferentfrommostcountries.BreakfastintheSpanishcultureiseasilytheleastimportantmealofthedaythefirstthingoccurringinthemorninguntilabout10:00am.ManySpaniards西班牙人skipbreakfastbutiftheydohavebreakfastitwilllikelybesomethinglightandsimplewhichmayconsistofcoffeehotchocolateorfresh﹣squeezedorangejuiceaccompaniedbyapieceoftoastwithjam.Aftersuchalightbreakfastfromaround10:30amtonoonbarsarefullofworkersfortheirmorningcoffeebreakswhoenjoyadrinkandasmallsnacktohelpsurviveuntillunchtime. Lunchthemostimportantmealofthedaygenerallyconsistsofseveralcourseswithalightfirstcoursesuchassouporsaladaheaviersecondcourseofmeatorfishfruitordessertfollowedbybreadandalsowineandwater. Lunchandthefamousnaptimeoccurfrom2pmuntil4pm.Mostshopsandcompaniescloseduringthistimetoallowtheirworkerstomaketheirwayhometoeat.Althoughthispausestillexiststhefamousnaptimeisrarelyusedforsleepingbutrathertransportationaspeoplegraduallylivefartherandfartherawayfromtheirworkplaces. Duetothislunchbreakmanyworkersdonotleavetheirworkuntilabout8pm.Typicallythisiswhentheywillhaveasmallsnacktogetthemthroughuntildinnertime.DinnersimilartolunchbutusuallylighterisalateaffairinSpainwhichisnormallyservedfrom9pmto10:30pm.InthesummertimeitiscommontoseeSpaniardssittingdowntoeataslateas12pm! 1Whichisusuallyservedaftersoupatlunch? A.Aglassofjuice B.Acupofwine C.Apieceofsteak D.Aplateofsalad 2WhendomostshopsandcompanieskeepopenafterlunchinSpain? A.From2pmto4pm B.From4pmto8pm C.From2pmto9pm D.From9pmto12pm 3Whatcanwelearnfromthetext? A.Spaniardsaretoobusytohavebreakfast. B.Spaniardsusuallyhaveanapfor2hours. C.Spaniardsusuallyfinishtheirworkat9pm. D.Spaniardsthinktheirlunchthemostimportant. 4Whatcouldbethebesttitleforthetext? A.ABusyWorkdayoftheSpanish B.FoodsServedatMealsinSpain C.UniqueDiningCustomsinSpain D.ComfortableLifeoftheSpanish
文中共有10处语言错误每句中最多有两处.请找出并按下列情况改正: 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:在错的词下划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. Todayourclassholdsatreeplantingactivitytheaimwastogetclosetothenatureorbeautifytheenvironment.InthemorningwetookbustoWesternhillwhereis5kilometersawayfromourschool.Inarrivalwebegantoworkimmediate.Somewerediggingholes.Somewerecarryingandplantingyoungtrees.Otherswerewateringit.Aftergettingtheworkdoneweputupaboardremindingpeoplenottoprotectthetrees.Atlastwetooksomephotostorecordourgreenaction. Seethelinesoftreesweallhadasenseofachievements.Wefeelit'sourdutytoprotectourenvironment.
Feathersarenotjustforflight.Theykeepbirdswarmandattractmates.AndforoneAustralianbirdfeathersevenhelpproduceanimportantsound﹣analarm. Peoplehadlongnoticedthesebirdsproducedtheseloudsounds.TrevorMurrayaresearcherattheAustralianNationalUniversitysaid.MysupervisorRobMagrathandMayHingeethoughttheywereusedasanalarm.Sotheydidsomeplaybacksandtheycouldshowquitestronglythatifyouplaybackthesesoundstootherbirdstheyfleestraightaway.SoIwasreallyinterestedinhowtheyproducethesoundwhetheritisactuallyasignalandwhetherit'sareliablesignal. Theteamfocusedtheirexperimentonspecificfeathersinthepigeon'swing.Wewereabletotargettheeighthprimaryfeatherwhichisunusuallynarrow.Andthenwealsoremovedondifferentsetsofbirdsthoseneighboringfeatherstheninthprimaryfeatherandtheseventhprimaryfeather.Andwewereabletoseewhentheeighthprimaryfeatherwasmissingthehighnotehadcompletelydisappeared.Sotheeighthprimaryfeatherproducedthathighnoteandtheninthprimaryfeatheractuallyproducedthelownote. Andifthebirdsarefleeingfromdangertheyproducealouderandhighersoundthantheydoduringanormaltakeoff.ThestudyisinthejournalCurrentBiology. Murrayandhiscolleaguesdidanotherexperimentwheretheyusedtherecordingstheymadetoobservethereactionsofotherpigeons.Wewereabletoseetheunusualeighthprimaryfeatherwasimportantforsignalingthealarm.Whenthateighthprimaryfeatherwasmissingtheyveryrarelyresponded.Theyalmostneverfled.Whereaswhentheninthprimaryproducesthesoundtheyfledjustasmuchastonormalalarms.Thisshowsusthisunusualprimaryfeatherisimportantforsignalingalarm. Thatmakesbirdsofafeatherfleetogether. 1WhatdoestheunderlinedwordtheyinParagraph2referto? A.Thebirds B.RobandMay C.Thefeathers D.Theloudsounds 2WhatdidRobMagrathandMayHingeefindoutaboutthebirds? A.Theyflyawayasagroup. B.Theyproducedifferentnotes. C.Theysendalarmswithfeathers. D.Theyattractmateswithfeathers. 3Whydidtheteamremovedifferentfeathers? A.Torecordthenotestheyproduce. B.Tokeepthepigeonsstayincages C.Tocomparetheirwidthandlength. D.Toobserveotherpigeons'reactions. 4AccordingtoMurrayandhiscolleagueswhydoestheunusualfeathersmattermost? A.Itkeepsthepigeonswarm B.Itrespondstoalarms C.Ithelpsbirdsflymorequickly D.Itsoundsalarmsofdanger.
化简比42的结果是2．判断题
Adulteducationcourses 1Whichcoursesarcsuitableforbeginners? A.WebDesignandArt. B.ComputerStudiesandwoodwork. C.WoodworkandWebDesign. D.ComputerStudiesandArt. 2Whichcourseawardsstudentsanofficialcertificate? A.Art. B.Woodwork. C.webDesign. D.ComputerStudies. 3Howmuchwillastudentwhoattendsonlyhalfofallthewoodworklessonspayintotal? A.￥30. B.￥360. C.￥250. D.￥180.
EveryyearfromMarchtoOctoberChristianMoullecalsoknownasBirdmanfliestotheskyaboardhislightaircraft.Howeverthe58﹣year﹣oldFrenchman'sdaily30﹣minuteflightisnotjusttoenjoytheimpressiveviewsbuttoguideflocks鸟群oflesserwhite﹣frontedgeese小白额雁throughsafemigration迁徙pathswhichthebirdscanteachfuturegenerations. Hisdeedbeganin1995whenhenoticedtheirdecliningpopulationinthewild.TopreventtheirnumbersfromdroppingMoullectriedtogetthegeesetofollowhimduringmigrationthatwouldprotectthemfrombirdhunters. Howevergettingadultgeesetofollowhisleadischallenging.AsyounggeeselearnandfollowwhomevertheyviewastheirparentMoullecdecidedtoraisethegeesefrombirth. TohelpraisefundsandawarenessofhisjobofprotectingnotjustthegeesebutotherbirdsworldwideaswellMoullecoftenallowspayingtouriststojoinhimonthe30﹣minute﹣longflightsaboardhisaircraft.Inadditiontothetrainedbirdsflyingalongsidethemvisitorswhocomefromasfarasa15﹣hourplaneflightawaycanenjoyavarietyofcraneandgeesespeciesaswellasbreathtakingviewsofcastlesandcities. Heoftenbringshiscameraalongfortheflightstakingphotosnotjustforthebreathtakingscenerybutforwhattheyconvey传达.MoullecbelievestheuseofagriculturalchemicalshasdoneharmtowildEuropeanbirdswithmorethanathirddisappearinginthelast30years.It'sadisasterhesaid.Mybeautifulpictureswithflyingbirdsshouldbeusedtotellthisstory. 1WhydoesBirdmanalwaysflytotheskyonhisaircraft? A.Toobservegeesealongtheirmigrationroutes. B.Tofollowgeesethroughsafemigrationpaths. C.Totakevisitorstooperatehisadaptedaircraft. D.Toguidegeeseflysafelyduringthemigration. 2WhatdoweknowaboutBirdman? A.Heisanaturelover. B.Heisabirdwatcher. C.Heisavolunteerpilot. D.Heisabirdhunter. 3WhatdoesMoullecoftentakephotosinhisflightsfor? A.Recordingtheuseofagriculturalchemicals. B.Showingseriousdamagecausedbychemicals. C.Describinghisexperienceswithflyingbirds. D.Capturingthebeautifulviewsofbirdsandcities. 4Whatcanbeasuitabletitleforthetext? A.BirdmanGuidesFlockstoLearntoFly. B.BirdmanFindsBirdsDisappearing. C.BirdmanHelpsFlocksSafelyMigrate. D.BirdmanProtectsBirdsFromHunters.
【观察猜想】如图①△ABC与△CDE都是等腰直角三角形直角边ACCD在同一条直线上连接AEBD．猜想AE与BD的数量关系是位置关系是不用证明 【探究证明】如图②在图①中取ABDEAD的中点MNP连接PMPNMN判断△PMN的形状并说明理由 【拓展应用】如图③把图②中的△CDE绕点C任意旋转若AC＝4CD＝2则△PMN面积的最大值为．
大正方形的边长为4厘米小正方形边长为2厘米大小正方形边长的比是大小正方形周长的比是大小正方形面积的比是．
分解因式2x2﹣18＝．
传话游戏由老师通知两名同学两名同学每人再通知两名同学以此类推每一次传话需5秒钟25秒后已经传了几个人
NewLivesforOldPhones Whenanewmobilephonestartstobesoldinstoresmanypeoplerushouttobuyone.Weallwantthenewestlatestthing.1. MikeTownsendworksatTotalRecallamobilephonerecyclingcompany.Don'tthrowyouroldphoneaway.2ifyouthrowitawayitgoeswithotherrubbishtobecomelandfill.Inotherwordsitisputinabigholeinthegroundanditbecomesabigproblemhesays. Mobilephonescontainsomepoisonousmaterials.Ifyourphonegoestoalandfillthesepoisonousmaterialscangetoutandgetintothewaterundertheground.That'sthewaterweneedtodrinkorwatergoesintoriversortheocean.3That'salotoflandfillandalotofpoisonousmaterials. AtTotalRecallweseparatetheoldphonesintopieces.Mostofthematerialsinthemobilephonescanberecycledandusedagain.4Forexamplephonebatteriescontainnickelandcadmium.Thenickelisusedtomakesteelandthecadmiumcanbeusedtomakenewbatteries.explainsMike. 5YoucanusuallyjusttakeitintoamobilephoneshopandtheywiltsendittoussaysMike. Sobeforeyouthrowthatoldmobilephoneawayuseitthelasttime:searchforarecyclernearyouandgivethemacall. A.Recyclingyouroldphoneiseasy. B.Sendittousandwe'llrecycleit. C.Howmuchisyouroldmobilephoneworth? D.Butwhatshouldwedowithouroldmobilephones? E.Millionsofmobilephonesarethrownawayeveryyear. F.Recyclingmaterialshelpskeeptheenvironmentgreenerandcleaner. G.Wetakeaparttheoldphonesandtheyareusedtomakenewproducts.
一本书共有80页小华第一天看了全书的第二天看了的页数和没看页数的比为24还剩多少页没看
甲数与乙数的比是53则乙数比甲数少20%．判断题
IfyouareinterestedinbothChina'sancientfinanceandarchitecturePingyaoisaplaceyoucan'tmiss. PingyaoAncientCity1locateinthecentralShanxiProvince.Chinaisawell﹣preservedexampleofatraditionalHanChinesecity.Whenitwasfoundedinthe1.4thcenturyitswallsaretenmetreshigh6163metresaroundandthreetofivemeterswideatthetop.Thewesternandeasternsidesofwallshavetwogates2thesouthernandnorthernwallseachhaveonegateonly. Fromthe19thcenturytotheearly20thcenturyPingyao3controlalmosthalfoftheeconomyofthecountryatitsboomingperiodwasafinancialcenterforthewholeofChina.There4beonceovertwentydraftbank'sheadoffices5branchesweredistributed6widearoundthewholecountryeveninsomewesternandsoutheasterncountries. TodaywhenotherChinese7cityhavebeenmorethanhappytoburytheirhistoryunderskyscrapersthis8originChineseWallStreetchoosesnottoOrdinarypeoplestilllive9thecity'shundredsofMingandQingDynastycourtyardsastheydidinthepast.ThiscityishelpingChineserediscoverthevalueofpreservingwhatlittle10leaveofthecountry'sancientbuildings.
如图圆锥的底面半径为3cm母线长为6cm那么这个圆锥的侧面积是cm2结果保留π．
化简比0.420
EachapplicanttoHarvardCollegeisconsideredwithgreatcare.WeconsidereachapplicanttoHarvardCollegeasawholepersonandputenormouscareintoevaluatingeveryapplication.Wehopeyouwillexploretheinformationinthissectiontounderstandwhatwelookforinouradmissionsprocess. HowtoApply SubmityourapplicationthroughtheCommonApplicationtheCoalitionApplicationortheUniversalCollegeApplication.EachistreatedequallybytheAdmissionsCommittee.Completeandsubmityourmaterialsassoonaspossibletoensurefullandtimelyconsiderationofyourapplication.ViewourApplicationTipsforstep﹣by﹣stepinformation. WhentoApply WhatWeLookFor WeseekpromisingstudentswhowillcontributetotheHarvardcommunityduringtheircollegeyearsandtosocietythroughouttheirlives.WhileacademicaccomplishmentisthebasicrequirementtheAdmissionCommitteeconsidersmanyotherfactors﹣strongpersonalqualitiesspecialtalentsorexcellencesofallkindsperspectivesformedbyunusualpersonalcircumstancesandtheabilitytotakeadvantageofavailableresourcesandopportunities. WeoutlineeverythingyouneedtoapplytoHarvard. Clickhttps:∥college.harvard.edu/admissions/applytogetdetailedrequirements. 1Wherecanyoufindstep﹣by﹣stepinformationofhowtoapply? A.CommonApplication. B.CoalitionApplication. C.UniversalCollegeApplication. D.ApplicationTips. 2WhichisthefinaldayforFinancialAidApplication? A.November1. B.January1. C.March1. D.May1. 3WhatisthebasicrequirementtoapplyforHarvardUniversity? A.Academicaccomplishment. B.Strongpersonalqualities. C.Specialtalents. D.Uniqueperspectives. 4Wheredoesthispassageprobablycomefrom? A.Traveljournal B.Businessnewspaper C.Fashionmagazine. D.Universitywebsite.
5==27÷=%=成
Bothhoneybeesandantsaresocialinsectsthatliveingroupscalledcolonies.Theysurvivebymeansoftheircollectiveintelligence.Theirdecision﹣makingpowerisdistributedthroughoutthegroup;thatisnooneantorbeemakesdecisionsforthegroup.Insteadtheyworktogether.AsDeborahM.GordonabiologistofStanfordUniversitysaysAntsaren'tsmart.Antcoloniesare.Thesameistrueforbeecolonies.Althoughbeesandantsarequitedifferentphysicallytheyhavealotincommonintermsoftheirbehavior.Specificallyhoneybeesandantshavesimilarroleswithinthecolonybothhavecommunicationsystemsandbothhavethecapacityoflearning. Antscommunicatebyusingchemicalscalledpheromoneswhichcanalertotherstodangerortoafoodsource.Forexamplewhenworkerantsfindapromisingsourcetheylettherestofcolonyknowhowtofinditbyleavingatrailofpheromonesonthewaybacktothecolony.Theotherantspickupthemessageusingtheirsenseofsmell.Beesontheotherhandusemovementtocommunicatewitheachother.Workerbeessendmessagetoeachotherbymeansofadance.Differentspeedsandmovementssenddifferentmessages.Forexamplewhenworkerbeescalledscoutsgoouttofindanewhoeforthecolonytheyreturnanddoadancefortheotherworkerbeesthatindicatesthelocationofthenewhomeandhowsuitableitis.Thefasterthescoutsdancethebetterthenewlocationis. Honeybeesandantsarebothcapableoflearning.OneChinesestudyfoundthatbeescanbetrainedtolearnandrememberaroutetoafoodsource.Theresearchersalsofoundthatbeescanbetaughttorecognizehiddenobjectsandusetheconceptsofsamenessanddifferencetoaccomplishcertaintasks.Antstakethisonestepfurther.RecentAmericaresearchhasshownthatantsnotonlyhavetheabilitytolearnbutalsocanteachtheirforagingskillstootheryoungerants.Theyobservedthatolderantsaccompanyyoungantsinsearchoffoodandteachthemtherouteandhowtoavoidobstacles. Aswecanseethesocialbehaviorofhoneybeesandantsisquitesimilar.Bothcoordinatecomplexactionsandaccomplishcrucialsurvivaltasksbycooperatingingroupsconsistingofmanyindividuals.Unintelligentastheymaybeasindividualsasgroupstheyoftenshowamazingbrillianceastheygoabouttheireverydayactivities. 1Whatdoantsandbeeshaveincommon? A.Theymakeuseofcollectiveintelligence. B.Theyliveinsimilar﹣sizedcolonies. C.Theyhavesmallleadershipgroupsthatmakealldecisions. D.Theyusethesamemethodtocommunicatewitheachother. 2Whatdocsthespeedofabee'sdanceindicate? A.Thedistancetoaneighboringcolony. B.Thequalityofanewcolonylocation. C.Thediscoveryofanewfoodsource. D.Thedirectiontoapotentialfoodsource. 3Inparagraph3howdocstheauthordemonstratetheideathatHoneybeesandantsarebothcapableoflearning? A.Byusingstatistics. B.Byexplainingreason. C.Bypresentingstudyfindings. D.Bystatingopinions. 4WhatdoestheunderlinedpartforagingskillsrefertointhethirdParagraph? A.Theskillsofcommunicating. B.Theskillsofsackingfood. C.Theskillsofleaning. D.Theskillsoffindinganewhome.
在读书月活动中学校准备购买一批课外读物．为使课外读物满足同学们的需求学校就“我最喜爱的课外读物”从文学艺术科普和其他四个类别进行了抽样调查每位同学只选一类如图是根据调查结果绘制的两幅不完整的统计图． 请你根据统计图提供的信息解答下列问题 1本次调查中一共调查了名同学 2条形统计图中m＝n＝ 3扇形统计图中艺术类读物所在扇形的圆心角是度 4学校计划购买课外读物6000册请根据样本数据估计学校购买其他类读物多少册比较合理
Mydadismyherobecauseheisbraveskilledandrespectful.Iknowmanypeoplesaytheirdadsaretheirheroesbutmydad1meaboutbecomingamanwhichis2importantforayoungboy. Respectgoesalongwaywithmydadasdoespatience.Asan3mydadmust4peopleeverydaysomeofwhomareniceandsomearenot.Eitherwayhe5hiswell﹣manneredattitude. Dadisnotafraidofmanythingsorifheishedoesn'ttellme6hewantstoseemtough.Hemaynotbeabigguybutsinceheworkswithhis7alldayheisverystrong.Dadworksoutdoorsinallkindsof8buttheworstthinghehastodois9upandworkinanattic顶楼inthemiddleofthesummer.Trustmethisisthe10placeyouwillexperienceasanelectricianandwhenyoucomeback11whatisinyourlungswillmakeyou12forhours. MydadandIhaveaverygood13.Wetalkaboutalmosteverything.Wegohuntingfishingandeverythingadadandsonwoulddo.MydadandIenjoyhiking14becauseitgivesustimeoutdoorstogetherandthereisnothinglikethat.Hehas15andtaughtmeeverythingIneedtoknowabout16. Iam17tobethesonofMikeC.andwouldnothaveitanyotherway.Peoplecomeuptomeallthetimeto18meIhaveagooddad.Itmakesmefeel19thatalotofpeoplethinkso20ofhim.Heisagoodteacherofmylifeandwoulddoanythingforme.Thisiswhymyfatherismyhero. 1A.arranges B.teaches C.worries D.reminds 2A.specially B.extremely C.nearly D.hardly 3A.worker B.officer C.electrician D.engineer 4A.lookafter B.dealwith C.waitfor D.searchfor 5A.offers B.makes C.hides D.keeps 6A.though B.unless C.until D.because 7A.brain B.mouth C.hands D.legs 8A.positions B.situations C.conditions D.destinations 9A.climb B.put C.send D.set 10A.coldest B.highest C.best D.hottest 11A.down B.over C.inside D.up 12A.rest B.cough C.ache D.sleep 13A.relationship B.friendship C.agreement D.companion 14A.widest B.least C.most D.latest 15A.learned B.referred C.shown D.collected 16A.animals B.nature C.study D.skills 17A.excited B.eager C.surprised D.proud 18A.ask B.warn C.tell D.promise 19A.well B.good C.nervous D.nicely 20A.easily B.seriously C.highly D.lightly
求比值
化简比
下列图案由正多边形拼成其中既是轴对称图形又是中心对称图形的是
下面数据分别用哪种统计图表示比较合适A．人离不开水成年人每天体内47%的水靠喝水获得39%来自食物含的水14%来自体内氧化时释放出来的水．B．某校五年级学生最喜欢的课外活动统计表如下．C．李行从一年级到五年级每年体检的身高记录如下．A用统计图 B用统计图 C用统计图
下列运算正确的是
常用的统计图有统计图统计图统计图．
热门题库
更多
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
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
湘公网安备 43130202000226号