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下面是实验室常用制取气体的装置图，根据装置图回答下列问题： （1）写出标有①②序号的仪器的名称：① ，② ． （2）实验室在B装置中用双氧水与二氧化锰混合制取氧气的化学方程式： ．...
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下列是实验室常用的装置图5-14完成下列问题1图5-14中仪器a的名称是_____________2
下列实验装置图是实验室中常用于制取气体的装置请据图回答下列问题1写出仪器a的名称2若用装置A.制取气
实验室常用右图装置制取二氧化碳气体并对所制的气体进行检验请回答下列问题1右图是完成上述实验的部分装置
下列是实验室制取气体的常用装置图请根据下图回答问题1写出仪器ab的名称ab2若实验室用高锰酸钾制取氧
如图是实验室制取氧气常用的装置根据装置图回答下列问题1写出图中标号仪器的名称a.2实验室用高锰酸钾制
如图是实验室制取氧气常用的装置根据装置图回答下列问题1写出图中标号仪器的名称ab2实验室用高锰酸钾固
下面是实验室制取氧气的装置图根据装置图回答下列问题1写出装置图中标有①②序号的仪器名称①②2实验室用
下列是实验室制取和收集气体的常用装置图请根据实验要求回答下列问题第2题图1请写出装置图A中标号①的仪
如图是实验室制取和收集气体的常用装置图请根据所给的装置图回答下列问题1请写出装置图A.中标号①的仪器
下图是实验室制取气体常用的几个装置图请回答有关问题11分写出以上装置中标出的仪器名称a_______
如图是实验室制取氧气常用的装置根据装置图回答下列问题1写出图中标号仪器的名称ab2实验室用高锰酸钾制
根据下列实验装置图回答问题1写出a的仪器名称______2在加入药品之前应对实验装置进行______
图是化学实验中常用的几种装置.请根据图回答下列问题1实验室制取二氧化碳应选用的发生装置是收集装置是2
根据下列实验装置图回答问题1写出A.图中a仪器的名称____2写出一个用装置B.制取气体的化学方程式
如图是实验室制取和收集气体的常用装置图请根据所给的装置图回答下列问题1请出装置图C中标号②的仪器名称
根据下列实验装置图回答问题1写出A.图中a仪器的名称____2写出一个用装置B.制取气体的化学方程式
下面是实验室制取氧气的装置图根据装置图回答下列问题A.B.C.D.E.1写出装置图中标有①②序号的仪
下列两组装置图都与我们学过的气体的制取和性质有关.根据如图A.～E.所给的装置回答问题①实验室用高锰
.如图是实验室制取和收集气体的常用装置图请根据所给的装置图回答下列问题1请写出装置图C.中标号②的仪
实验室选用右图所示装置制取和收集气体根据要求回答下列问题.1指出标号的仪器名称①②.2实验室用B装置
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15分LastyearmybrotherandIwenttoMiamiforavacation.Someofmyfriendswho1betherebeforesaiditwasawonderfulholidaydestination.Beforewewentwehadplannedformonths.Whenthedaycamewewereready. Afterourplanelandedwewenttothehotel.Wehadmadeourreservationsixmonths2earlybutthemanatthefrontdesksaidtherehadbeenamistake.We3tellthatourroomshadn'tbeenreservedforthatweek4fortheweekafter.Ididn'tunderstand5thiswouldhappenandmycreditcardhadalreadybeencharged6thereservation.What'sworsethehotelhadbeenfullybooked.Whenwewerewonderingwhattodothemanagercameout.Shewas7surprisehelpful.SheapologizedforthemistakeandgaveusaspareVIProomon8topfloor.Wehadneverstayedinsuchanamazingroomandweweren'tchargedextra. ThenextdaymybrotherandIwenttothebeach9wewatchedsomepeopleplayvolleyball.Wegotalittle10sunburnbutthedayhadbeensorelaxingthatwedidn'tmind.
10分Bullying欺凌isaprobleminmanyschools.Maybelotsofyouhaveevercomeacrossschoolbullies.1 Ignorethebullyandwalkaway.It'sdefinitelynotacoward'sresponse.Sometimesitcanbeharderthanlosingyourtemper.Walktallandholdyourheadhigh.2 Holdtheanger.Whodoesn'tgetreallyupsetwithabully?3Bullieswanttoknowtheyhavecontroloveryouremotions.Workoutyourangerinotherwayssuchasthroughexerciseorwritingitdown. 4Howeveryouchoosetodealwithabullydon'tusephysicalforce.Notonlyareyoushowingyourangerbutyoucanneverbesurewhatthebullywilldoinresponse.Youaremorelikelytobehurtandgetintotroubleifyouuseviolenceagainstabully.Youcanstandupforyourselfinotherwayssuchasgainingcontrolofthesituationbywalkingaway. Talkaboutit.Itmayhelptotalktoaguidanceadvisorteacherorfriend.5Talkingcanbeagoodoutletforthefearsandfrustrationsthatcanbuildwhenyou'rebeingbullied. A.Takechargeofthesituation. B.Thistypeofbodylanguagemeansyouarenoteasilyharmed. C.Herearesomethingsyoucandotofightbullying. D.Don'tgetphysical. E.Butthat'sexactlytheresponseheorsheistryingtoget. F.Someadultsbelievethatbullyingispartofgrowingup. G.Peopleabovecangiveyouthesupportyouneed.
15分Climatechangehascausedariseinsealevels.Thishasincreasedtheamountofsaltinfreshwater1useoncoastalfarms.Asaresultfarmersare2gradualunabletousefieldsclosetothesea.HoweverMarcVanRijsselbergafarmerintheNetherlandsisnowusinga3mixofseaandfreshwater4growhealthyandtastyvegetables.HeteamedupwithscientistsfromtheFreeUniversityanddividedafarm5eightnegatedareas.Separatepipespumpedfreshandseawaterandacomputerprogramcreatedwaterwitheightlevelsofsalinity含盐度.Thewaterlevelsandthelevelsofsalinitywas6controlbycomputerizedmeasuringdevicescalledsensors.Mr.VanRijsselbergsaidhewasabletoharvestvegetablesfrommostoftheeighttestingareas.Hesaidthevegetablesweresmallerthan7growninfreshwater.Buthesaidtheyalsohadmoresugarandsaltsotheytastedmuch8good.Hefoundthatpotatoesgrewbetterthantheothervegetablesinthecombinationofseaandfreshwater.Mr.VanRijsselbergsaidfourkindsofthesepotatoeswouldbesettoPakistan9thousandsofhectaresofland10damagebysalinizationlastyear.
某校九年级1班40名同学期末考试成绩统计表如下． 下列结论①成绩的中位数在80≤x＜90②成绩的众数在80≤x＜90③成绩的平均数可能为70④成绩的极差可能为40．其中所有正确结论的序号是．
25分随着人们生活水平的提高旅游成了大家生活的一部分.假如你是李华正在参加网络征文Beingacivilizedtourist. 内容:1.旅游现状;2.整改措施 要求:100单词左右
89岁的侯云德院士获得2017年国家最高科学技术奖这位著名的医学病毒学专家发现最小的病毒的半径仅有0.000009毫米将0.000009用科学记数法表示应是
如果代数式有意义那么x的取值范围是．
10分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处错误每句中最多有两处.错误涉及一个单词的增加删除或修改. Istillrememberamathslesson.Mymathsteachercopiedachallengingproblemontheblackboardandasksthewholeclasswhethertherewouldbeonestudentwhoknewwhattoworkitout.Severalminutespassedbutthewholeclasswasincompletelysilence.AsmatteroffactIcameacrosstheprobleminabooktheotherday.HoweverIwalkedtotheblackboardandworkeditoutinnotime.Whatasurprisingexpressionwasonmymathsteacher'sface!Hefeltveryhappythathepraisedmeonpublic.SincethenmathshasbeenbecomeoneofmyfavoritesubjectandIhavealsomaderapidprogressinmaths.
8分Howfitareyourteeth?Areyoulazyaboutbrushingthem?Neverfear:Aninventorisonthecase.Anelectrictoothbrushsenseshowlongandhowwellyoubrushanditletsyoutrackyourperformanceonyourphone. TheKolibreetoothbrushwasexhibitedattheInternationalConsumerElectronicsShowinLasVegasthisweek.ItsenseshowitismovedandcansendtheinformationtoanAndroidphoneoriPhoneviaaBluetoothwirelessconnection. Thetoothbrushwillbeabletoteachyoutobrushrightdon'tforgettheinsidesoftheteeth！andmakesureyou'rebrushinglongenough.It'skindoflikehavingadentistactuallywatchyourbrushingonadaytodaybasissaysThomasServaltheFrenchinventor. Thetoothbrushwillalsobeabletotalktootherapplicationsonyourphonesodeveloperscouldforinstancecreateagamecontrolledbyyourtoothbrush.Youcouldscorepointsforbeatingmonstersamongyourteeth.WetrytomakeitsmartbutalsofunServalsays. Servalsayshewasinspiredbyhisexperienceasafather.Hewouldcomehomefromworkandaskhiskidsiftheyhadbrushedtheirteeth.TheysaidyesbutServalwouldfindtheirtoothbrushheadsdry.Hedecidedheneededabrushthatreallytoldhimhowwellhischildrenbrushed. ThecompanysaystheKolibreewillgoonsalethissummerforD|S99toD|S199dependingonfeatures.TheU.S.isthefirsttargetmarket. Servalsaysthatonedayit'llbepossibletoreplacethebrushonthehandlewithabrushingunitthatalsohasacamera.Thecameracanevenexamineholesinyourteethwhileyoubrush. 1WhichofthefollowingmightmaketheKolibreetoothbrushfun? A.Itcanbeusedtoupdatemobilephones. B.Itcanbeusedtoplaymobilephonegames. C.Itcansendmessagestootherusers. D.Itcantalktoitsdevelopers. 2WhatcanweinferaboutServal'schildren? A.Theywereunwillingtobrushtheirteeth. B.Theyoftenfailedtocleantheirtoothbrushes. C.Theypreferredtouseatoothbrushwithadryhead. D.TheylikedbrushingtheirteethafterServalcamehome. 3WhatcanwelearnaboutthefuturedevelopmentoftheKolibree? A.Thebrushhandlewillberemoved. B.Amobilephonewillbebuiltintoit. C.Itwillbeusedtofillholesinteeth. D.Itwillbeabletocheckusers'teeth. 4WhatisParagraph5mainlyabout? A.HowServalfoundouthiskidsliedtohim. B.WhyServalthoughtbrushingteethwasnecessary. C.HowServaltaughthiskidstobrushtheirteeth. D.WhatinspiredServaltoinventthetoothbrush.
矩形AOBC中OB＝8OA＝4．分别以OBOA所在直线为x轴y轴建立如图1所示的平面直角坐标系．F是BC边上一个动点不与BC重合过点F的反比例函数y＝k＞0的图象与边AC交于点E． 1当点F运动到边BC的中点时求点E的坐标 2连接EFAB求证EF∥AB 3如图2将△CEF沿EF折叠点C恰好落在边OB上的点G处求此时反比例函数的解析式．
已知关于x的方程x2+mx﹣2＝0的两个根为x1x2若x1+x2﹣x1x2＝6则m＝．
某地下车库出口处安装了“两段式栏杆”如图1所示点A是栏杆转动的支点点E是栏杆两段的联结点．当车辆经过时栏杆AEF最多只能升起到如图2所示的位置其示意图如图3所示栏杆宽度忽略不计其中AB⊥BCEF∥BC∠AEF＝143°AB＝AE＝1.3米那么适合该地下车库的车辆限高标志牌为多少米结果精确到0.1．参考数据sin37°≈0.60cos37°≈0.80tan37°≈0.75
某班为奖励在学校运动会上取得好成绩的同学计划购买甲乙两种奖品共20件．其中甲种奖品每件40元乙种奖品每件30元．如果购买甲乙两种奖品共花费了650元求甲乙两种奖品各购买了多少件．设购买甲种奖品x件乙种奖品y件．依题意可列方程组为
25分假定你是李华本已约好与Kelvin今天4月8日晚上一起看电影捉妖记MonsterHunt.但你临时有事他打篮球未回故给他写留言条.要点如下:1.临时有事要做.2.具体更改的见面时间地点.3.此事已告知谁.4.见字告知.注意:1.词数100左右.2.可以适当增加细节以使行文连贯.3.开头结尾已给.
6分 CampAll﹣Star OneofaKindSummerCampsforKids WelcometoCampAll﹣StaryourNo.1summersportscampforkids!LocatedonthefamousKentsHillSchoolcampusbythebeautifullakeCampAll﹣Starhostskidsfromaroundtheworld.Whenthinkingaboutyournextovernightsummercampconsiderthebest﹣CampAll﹣Star! GreatSportsSummerCampsforKids CampAll﹣StarstandsoutamongthesuccessfulcampsintheU.S.Wehavethebestsportsfieldsandcourtstomakeyourchild'ssportscampexperienceasuccessfulone.Yourchildcanenjoyplayingforhoursinanyofourmorethan30sportsandactivitieseachday.Ourcampertostaffrateisthreetoonewhichmakesitpossibleforchildrentoreceivemorecarefulinstruction. Wehaveawidevarietyofactivitiesandsportstochoosefrom:fishingdancebasketballsoccerbaseballandtennis.Boysandgirlsaged8﹣16cancustomizetheirownschedulesinour234or6weeksummercampsessionforkids. TheaimofCampAll﹣Staristodevelopathleticskillsencourageabilitiesinleadershipfairplayandteamworkandprovideafunrewardingandmemorablesummersportscampexperience.Ourstaffhavetheexperienceandqualifiedtrainingnecessarytoensurethatyourchildhasasuccessfulmemorableandenjoyabletimeatoursummercamp. CallTodayAboutOurOvernightSummerCampsforKids Don'tletyourkidswasteanothersummerplayingvideogamesandsittingaround.Letthemenjoytheirtimeandgetsomeexerciseatourexcitingandfriendlysummersportscamp.Informationforourupcomingcampscanbefoundonourwebsite.Foradditionalinformationorquestionscontactustoday.WehopeyourkidscanjoinusatCampAll﹣Star! 1CampAll﹣Starstandsoutamongtheothersbecauseit. A.issurroundedbyabeautifullake B.providesvariousactivitiesandsports C.offerstimelyinformationonitswebsite D.allowschildrentoplayoutsidealldaylong 2OneofthegoalsofCampAll﹣staristo. A.firekids'imagination B.buildupkids'confidence C.developkids'leadershipskills D.promotekids'self﹣control 3Thisadvertisementisintendedfor. A.parents B.coaches C.staff D.Campers
8分Grown﹣upsareoftensurprisedbyhowwelltheyremembersomethingtheylearnedaschildrenbuthaveneverpracticedeversince.Amanwhohasnothadachancetogoswimmingforyearscanstillswimaswellaseverwhenhegetsbackinthewater.Hecangetonabicycleaftermanyyearsandstillrideaway.Hecanplaycatchandhitaballaswellashisson.AmotherwhohasnotthoughtaboutthewordsforyearscanteachherdaughterthepoemthatbeginsTwinkletwinklelittlestarorrememberthestoryofCinderellaorGoldilocksandtheThreeBears.Oneexplanationisthelawofoverlearningwhichcanbestatedasfollows:Oncewehavelearnedsomethingadditional额外的learningtrialsincreasethelengthoftimewewillrememberit.Inchildhoodweusuallycontinuetopracticesuchskillsasswimmingbicycleridingandplayingbaseballlongafterwehavelearnedthem.WecontinuetolistentoandremindourselvesofwordssuchasTwinkletwinklelittlestarandchildhoodtalessuchasCinderellaandGoldilocks.Wenotonlylearnbutoverlearn.Themultiplicationtables乘法口诀表areanexception例外tothegeneralrulethatweforgetratherquicklythethingsthatwelearninschoolbecausetheyareanotherofthethingsweoverlearninchildhood.Thelawofoverlearningexplainswhycramming突击学习foranexaminationthoughitmayresultinapassinggradeisnotasatisfactorywaytolearnacollegecourse.Bycrammingastudentmaylearnthesubjectwellenoughtogetbyontheexaminationbutheislikelysoontoforgetalmosteverythinghelearned.Alittleoverlearningontheotherhandisreallynecessaryforone'sfuturedevelopment.1WhatisthemainideaofParagraph1?A.Peoplerememberwellwhattheylearnedinchildhood.B.Childrenhaveabettermemorythangrown﹣ups.C.Poemreadingisagoodwaytolearnwords.D.Storiesforchildrenareeasytoremember.2Theauthorexplainsthelawofoverlearningby.A.presentingresearchfindingsB.settingdowngeneralrulesC.makingacomparisonD.usingexamples3Accordingtotheauthorbeingabletousemultiplicationtablesis.A.aresultofoverlearningB.aspecialcaseofcrammingC.askilltodealwithmathproblemsD.abasicsteptowardsadvancedstudies4Whatistheauthor'sopiniononcramming?A.Itleadstofailureincollegeexams.B.It'shelpfulonlyinalimitedway.C.It'spossibletoresultinpoormemory.D.Itincreasesstudents'learninginterest.
如图1在矩形ABCD中点E在CD上∠AEB＝90°点P从点A出发沿A→E→B的路径匀速运动到点B停止作PQ⊥CD于点Q设点P运动的路程为xPQ长为y若y与x之间的函数关系图象如图2所示当x＝6时PQ的值是
在﹣34﹣25四个数中任意两个数之积的最小值为．
的值等于
如图已知在▱ABCD中AE⊥BC于点E以点B为中心取旋转角等于∠ABC把△BAE顺时针旋转得到△BA′E′连接DA′若∠ADC＝60°AD＝5DC＝4则DA′的大小为．
已知a为整数且满足＜a＜则a的值为
先化简再求值其中x从﹣223五个数中适当选取一个．
6分 BLOODDRIVE&MARROW骨髓REGISTRATION Thesepatientsdeserveachanceatanormalhappyfutureandtheyrelyonthekindnessofstrangerstomakethathappen. ﹣DaisyIsabelle'sMother IsabelleisthedaughterofDaisyandSamanMirzaei.InJanuary2008Isabellewasdiagnosed诊断withageneticblooddisorderbetathalassemia.Isabelle'sbodyisunabletoproducehealthyredbloodcells.AsaresultIsabellehasbeenreceivingbloodtransfusions输血every4﹣6weekssinceshewas11monthsold.Alifetimeofregulartransfusionscanleadtoseriousmedicalproblems.Heronlychanceatanormalhealthylifeistohaveamarrowtransplant.IsabelleisanonlychildsodoctorshavestartedasearchforanunrelatedmarrowdonorthroughtheBeTheMatchRegistry.TheMirzaeifamilyasksthatyouconsiderhelpingpatientslikeIsabellebyregisteringtobeamarrowdonorandgivethegiftoflifethegiftofblood. HeldatWileyHall WednesdayMarch262014 BehindHeathmanDormitory/ButterfieldRd. 12:00PM﹣6:00PM Don'tforgettobringyourdriver'slicenseoranotherformofidentificationwhenyoudonate. Visitwww.ribc.orgtomakeanappointmentSponsorCode3390. FREEKingstonPizza!！! www.ribc.org800﹣283﹣8385 TheRhodeIslandBloodCenterdistributesbloodproductstohospitalsinRhodeIslandandSouthernNewEngland. 1Wecanlearnfromthepassagethat. A.theblooddriveisorganizedbyIsabelle'smother B.Isabellereceivesbloodtransfusionsregularly C.Isabellehasbeenillfor11months D.doctorswillsponsorIsabelle'sfamily 2ThosewhowanttohelppatientslikeIsabellecan. A.cometoWileyHalleveryWednesday B.visitwww.ribc.orgforanappointment C.contacttheirparentsat8002838385 D.callathospitalsinRhodeIsland 3Tobeamarrowdonoryoumust. A.bearelativeofthepatient B.carryadriver'slicense C.beatleast18yearsold D.applytoMichael'sFund
如图直线AB与CD相交于点OEO⊥CD于点OOF平分∠AOC若∠BOE∠AOC＝45则∠EOF为度．
下列计算正确的是
10分 TheiPonGeneration Todayitiscommontoseepeoplewhowalkaboutwithcoloredwireshangingfromtheirearswherevertheygo.Theymoveaboutintheirpersonalbubblessometimesunawareofwhat'shappeningaroundthem.1Outsidelifeisshutout.Soareyouoneofthem? Forme;walkingaroundinmyownpersonalbubbleisperfect.2What'sevenbetterwearingearphonesseemstogiveasignaltopeoplewhichsays;I'mnotavailableforchattingatthemoment. Supposeyou'reatworkandabouttomakeanincrediblebreakthrough?butacolleaguesuddenlyturnsup.Atthisprecisemomenttheslightestdisturbancewouldbreakyourconcentration.3OnceagainthosewireshangingfromyourearswouldbesuretogivethatGoaway!signal. 4It'sprobablypartofthegrowingupstagewhentheyjustwanttoignoretheirwholefamily.Whiletheirmothersgivethemlecturesaboutwhytheyshoulddotheir'Yes.Mum.''Problemsolved. Prettysoonnotonlywillwehaveprettycoloredwireshangingfromourears﹣butalsoourbrainswillbedirectlypluggedintosomenewhigh﹣techinstrument.We'llbeinavirtual虚拟的worldcommunicatingwitheveryoneelseorchoosingnottoaswelike.Inthisworldwewillallbepermanentlypluggedin.5Andtheyarechangingoursocialhabitsalongtheway. Intheendthereisathinlinebetweenusingtechnologyasatoolformakinglifebetterandbeingaslavetoit!It'ssostrange﹣suddenlyIdon'tfeellikewearingmyearphonesanymore. A.Ourinstrumentsarechangingquickly. B.Ialsohavewireshangingfrommyears. C.Inthehomesituationteenagerslovethesewires. D.Idon'thavetodealwiththenoisefromtheenvironment. E.AfterallIamlisteningtomyfavouritemusicandwouldrathernotbedisturbed. F.Listeningtomusicthroughearphonesistheperfectwaytoignoresuchinterruptions. G.Theywalkaroundintheirownspaceswiththeirpersonaldigitalnoisereductionsystems.
如图将△ABC绕点A旋转任意角度得到△AB'C'连接BB'CC'则BB'CC'等于
30分Inthediningroomofmygrandfather'shousestoodamassivegrandfatherclock.Mealsinthatdiningroomwerea1forfourgenerationstobecomeone.Thetablewasalways2withfoodfromwonderfulfamilyrecipes食谱allcontaining3asthemainingredient成分.Andalwaysthatgrandfatherclockstoodlikeatrustedoldfamily4sharingourhappiness.AsIwasachildtheoldclock5me.Iwatchedandlistenedtoitduringmeals.I6howatdifferenttimesofthedaythatclockwouldstrikewithawonderful7.Yearafteryeartheclockstruckapartofmy8apartofmyheart.Evenmorewonderfultomewaswhatmygrandfatherdideachday.He9woundthatclockwithaspecialandmagickeywhich10theclocktickingandstriking.Heneverletthatclockwinddownand11.Whenwegrandkidsgotalittleolderheshowedushowto12theclock.SeveraldaysaftermygrandfatherdiedIenteredthediningroomwithtearsflowing13.Theclockstooddesertedly14seemingsmallerandnotasmagnificentasbefore.Icouldn't15tolookatit.Yearslatermygrandmothergavemetheclockandthekey.Theoldhousewasquiet.Iopenedtheclockdoorwithmyshakinghand.Then16reverently虔诚地Ienteredthekeyandwoundtheclock.Itsprangto17.Tick﹣tocktick﹣tocklifeandchimeswere18intothediningroomintohouseandintomy19.Inthemovementofthehandsoftheclockmygrandfather20again.1A.party B.time C.place D.situation2A.filled B.cleared C.spread D.left3A.wine B.surprise C.love D.fish4A.friend B.guard C.solider D.lawyer5A.disappointed B.appealed C.surprised D.comforted6A.questioned B.remembered C.doubted D.wondered7A.sound B.noise C.voice D.ring8A.studies B.opinions C.memories D.brains9A.strangely B.usually C.carefully D.eagerly10A.got B.kept C.prevented D.set11A.break B.fall C.stop D.move12A.wind B.repair C.read D.clean13A.unexpectedly B.gently Cdifficultly D.freely14A.dumb B.alone C.quiet D.noisy15A.help B.bear C.hope D.insist16A.slowly B.quickly C.unwillingly D.naturally17A.feet B.hands C.sense D.life18A.breathed B.sung C.blown D.sent19A.mind B.eyes C.heart D.hands20A.survived B.lived C.showed D.left
1观察推理如图①在△ABC中∠ACB＝90°AC＝BC直线l过点C点AB在直线l的同侧垂足分别为ED．求证△AEC≌△CDB． 2类比探究如图②在Rt△ABC中∠ACB＝90°AC＝4将斜边AB绕点A逆时针旋转90°至AB′连接B′C求△AB′C的面积． 3拓展提升如图③在△EBC中∠E＝∠ECB＝60°．EC＝BC＝3点O在BC上且OC＝2动点P从点E沿射线EC以每秒1个单位长度的速度运动连接OP将线段OP绕点O逆时针旋转120°得到线段OF．要使点F恰好落在射线EB上求点P运动的时间t．
在一个不透明的口袋里有红黄蓝三种颜色的小球这些球除颜色外都相同其中有5个红球4个蓝球．若随机摸出一个蓝球的概率为则随机摸出一个黄球的概率为
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