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如图,四边形ABCD内接于⊙O,DA=DC,∠CBE=50°,则∠DAC的大小为 .
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如图在⊙O.的内接四边形ABCD中点E.在DC的延长线上.若∠A.=50°则∠BCE=.
如图四边形ABCD内接于⊙O若四边形ABCO是平行四边形则∠ADC的大小为
45°
50°
60°
75°
如图四边形ABCD是⊙O.的内接四边形若∠C.=65°则∠A.=_______°.
如图四边形ABCD是⊙O.的内接四边形∠B.=70°则∠D.的度数是
110°
90°
70°
50°
如图四边形ABCD中已知AB∥CDAD∥EC∠CEB=∠CBE四边形ABCD是等腰梯形吗如果是请说明
如图四边形ABCD内接于⊙ODA=DC∠CBE=50°则∠DAC的大小为.
如图四边形ABCD内接于⊙O.若四边形ABCO是平行四边形则∠ADC的大小为
45°
50°
60°
75°
如图四边形ABCD内接于⊙O.四边形ABCO是平行四边形则
45°
50°
60°
75°
如图四边形ABCD内接于⊙O.若四边形ABCO是平行四边形则∠ADC的大小为
45°
50°
60°
75°
如图在⊙O.的内接四边形ABCD中点E.在DC的延长线上.若∠A.=50°则∠BCE=.
如图四边形ABCD内接于⊙O.若四边形ABCO是平行四边形则∠ADC的大小为
45°
50°
60°
75°
如图四边形ABCD内接于⊙O.若四边形ABCO是平行四边形则∠ADC的大小为
45°
50°
60°
75°
四边形ABCD为圆O.的内接四边形已知∠BOD=100°则∠BCD=.
如图二所示四边形ABCD为⊙O.的内接四边形∠BCD=120°则∠BOD的大小是
80°
120°
100°
90°
如图四边形ABCD内接于⊙ODA=DC∠CBE=50°则∠DAC的大小为
130°
100°
65°
50°
如图四边形ABCD为⊙O.的内接四边形已知∠BOD=100°则∠BCD的度数为
50°
80°
100°
130°
如图四边形ABCD为⊙O的内接四边形已知∠BCD=110°则∠BAD=°.
如图四边形ABCD内接于⊙O.∠DAE是四边形ABCD的一个外角且AD平分∠CAE.求证DB=DC.
四边形ABCD为圆O.的内接四边形已知∠BOD=100°则∠BCD=.
如图四边形ABCD内接于⊙O四边形ABCO是平行四边形则∠ADC=
)45º (
) 50º
60º
75º
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将过量的铁粉加入CuNO32和AgNO3的混合溶液中充分反应后过滤下列对滤渣和滤液的说明中不正确的是
【问题探究】课堂上老师提出了这样的问题“如图1在△ABC中∠BAC=108°点D是BC边上的一点∠BAD=72°BD=2CDAD=4求AC的长”.某同学做了如下的思考如图2过点C作CE∥AB交AD的延长线于点E进而求解请回答下列问题 1∠ACE=度 2求AC的长. 【拓展应用】 如图3在四边形ABCD中∠BAD=120°∠ADC=75°对角线ACBD相交于点E且AC⊥ABEB=2EDAE=2则BC的长为.
10分假如英语课上老师要求同臬之间交换修改作文W你修改你M巣%的以下作文.文中共有10处语言错误苺句中伋多有两处错误.钟处错汉仅涉及一个iYUti】的增加删除成修改. 增加在缺问处加一个漏字符号A并在其下面写出该加的词. 删除把多余的同用斜线\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同. 注意1•每处错误及修改均仅限一词 2.只允许修改10处多者从第11处起不计分. Thismorningourschoolorganizedusstudentstopayingastudyvisit. WerodethebusattheschoolgatethengotoffatCityRevolutionaryMemorialat7﹣50.Therewelistentostoriesaboutrevolutionariesandpresentedflowers.At930wearrivedatthehomefortheoldandplayedmusicforthemhappy.Theneveryonechattedwithelderlypeoplesbringingthemjoy.Laterwereachedatourcity'sspecialeducationschoolwhichwesawdeafandblindstudentstaughtindifferentmethods.Wegavetheirgiftsdonatedbyourclass.Alsoweplayedgameswiththemhopedwecoulddomore. At1130wereturnedtoourschool.Whataimpressiveexperience!
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如图所示为实验室中常见的气体制备干燥收集和性质实验的部分目要求回答下列问题 1以石灰石和稀盐酸为原材料在实验室中制备并收集干燥的二氧化碳气体.按照要求设计实验装置连接仪器并检验装置的气密性. ①所选仪器的连接顺序为填写仪器序号字母 ②用石灰石和稀盐酸制取二氧化碳的化学方程式为 ③若将纯净的二氧化碳气体通入装置G石蕊试液中试液显色. ④将大量二氧化碳气体通入盛有大量澄清CaOH2溶液的大烧杯中烧杯中溶液的质量与之前相比会填“变大”“变小”或“不变”之一 3若以过氧化氢溶液为原料以二氧化锰为催化剂在实验室中制备干燥的氧气用来测定CuO和Cu的混合物样品中铜的质量仪器的连接顺序是A→D→C. ①D的作用是 ②加热过程中装置C中的现象是 ③欲通过测量反应前后C处大玻璃管质量的增加来计算混合物中Cu的含量充分反应后C处大玻璃管质量增加0.5克则混合物中Cu的质量为g.
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“绿水青山就是金山银山”北京市民积极参与义务植树活动.小武同学为了了解自己小区300户家庭在2018年4月份义务植树的数量进行了抽样调查随即抽取了其中30户家庭收集的数据如下单位棵 112323233433433 534344545343456 1对以上数据进行整理描述和分析 ①绘制如下的统计图请补充完整 ②这30户家庭2018年4月份义务植树数量的平均数是众数是 2“互联网+全民义务植树”是新时代首都全民义务植树组织形式和尽责方式的一大创新2018年首次推出义务植树网上预约服务小武同学所调查的这30户家庭中有7户家庭采用了网上预约义务植树这种方式由此可以估计该小区采用这种形式的家庭有户.
8分DatongamajorcoalproducerinnorthChina'sShanxiProvince300kmfromBeijingwasnotoriousforitspollutedair.Howeverthesituationhaschangedinrecentyearsasthecitypromotesanenergyrevolutionwiththefocusonencouragingnew﹣energyvehiclesanddevelopingwindandsolarpower. Datonghasadvantagesfordevelopingthesolarindustrysinceitenjoys2800hoursofsunshineonaverageannually.Alsoithasrichlandresourcesincludingsunkenlandtheremainsofcoalmining.Thesolarpanelsinthesunkenareaarewidelyspacedwithbushesplantedinbetweentoconservewaterandsoilandpromoteecologicalprotection. Inadditionitsstrongpowergrid输电网cantransmittheelectricityproducedbysolarpowertoBeijingTianjinandsomecitiesinneighboringHebeiProvince. Datongalsohasascienceandtechnologyparktopromotescientificnewideasandappearanceofindustriessuchashigh﹣endequipmentmanufacturinge﹣commerceculturetourismandecologicalagriculture. Howevertheenergyrevolutionisnotmeanttoendtheuseofcoalbuttopromotecleanandefficientconsumption. TheDatongCoalMineGrouphasbuiltacirculareconomyparktopromotegreendiversifiedandlow﹣carboncoaluse.Acirculareconomyisaneconomicsystemtoreducewastegenerationandmakefulluseofresources. Thetransformationofenergystructurehaspromotedthedevelopmentoftourismintheancientcitywithawealthofhistoricalandculturalsites.Todayevenintheoff﹣seasonofNovemberandDecemberfmanytouristsstillgosightseeingorrecuperation疗养.AhiRh﹣HpeedrailwaywillbecompletedthisyearreducingthetraveltimebetweenBeijingandDutongto100minuteswhichisexpectedtopromotethenumberofvisitors. 1Whatdoestheunderlinedwordnotoriousinthefirstparagraphmean? A.Convenient. B.Essential. C.Suitable. D.shameful. 2WhycanDatongsucceedindevelopingnewenergy? A.Becauseithasrichcoalresource. B.Becauseithasattractivetourism. C.Becauseithasparticulargeographyandscientifictechnology. D.Becauseithasfriendlypeopleandpotentialeconomicsystem. 3WhatcanwelearnaboutDatong? A.Itssolarpowerisonlyprovidedforitownuse. B.Ithasstoppedproducingcoalbecauseofpollution. C.NovemberandDecemberareitsbesttouristseason. D.Energytransformationhasbenefiteditinmanyaspects. 4Whatisthebesttitleforthetext? A.EnergyrevolutioninDatong B.Datong'spromisingtourism C.Solarpowerandwindenergy D.NewdevelopmentofDatong
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要除去下列物质中混有的少量杂质括号内为杂质所用的试剂和操作都正确的是
欲测定某碳酸钠样品中碳酸钠的质量分数取13.25g含有氯化钠杂质的碳酸钠样品加入50g14.6%的盐酸溶液二者恰好完全反应试求 1样品中碳酸钠的质量分数 2反应后溶液中氯化钠的质量分数.结果精确到0.1%
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8分Kindergartenoutside?Yesindeed.It'spartofagrowingworldwidetrendtowardoutdooreducation.TheschoolsarecalledForestKindergartens. NowthenumbersaresmallintheU.S.buttheideaiswellestablishedinEuropewithschoolsinScotlandEnglandandSwitzerland.ByfarmostofsuchschoolsareinGermanywhichhasmorethan400Waldkindergartens. Childrenattendingsuchparticularschoolenjoyagoodamountofoutdooreducationeachdayrainorshine.Somelessonsarefocusedonnatureothersareacademictopicsdeliveredinanaturalsetting.Inallcasesstudentsareactive﹣notsittingatdesksoronmatsonthefloorbutwalkingrunningjumpingsolvingproblemslikehowtogetthemudoffthebottomsoftheirshoesbeforetheirparentsfindout. Attheseforestkindergartensstudentslearnsciencebyobservinganddoingitlearnmathbyapplyingittothenaturalworldaroundthemlearnlettersandwordsbyputtingthemtogetherusingsightsandsounds.Thechildrenlearntomakecomparisonsusingnaturalthingslikeapplesandrocks.Theydevelopanappreciationforanimalsandplantsintheirnaturalenvironment﹣notjustbylookingatpicturesinabookoronacomputerscreen. Someofthescienceactivitiesinvolveteamworklikeexplainingthebestwaytomoveaheavyobjectshowinghowalever杠杆works.Inothersessionsteachersencouragestudentstodeveloptheirmotorskillsbybuildingwoodentoolssuchashammersandknives. Thesestudentsalsolearnhowtogetalongwithoneanotherindividuallyandinagroup.Theyalsodevelophealthylevelsofself﹣confidencejustfrombeingabletodotheeverydayactivitiesthattheschooloffers. Inatimewhensomanychildrenarebeingclassifiedasobesebecauseoflongtimewatchingtelevisionandplayingvideogamestheseoutdoorschoolshelpchildrenlearnjustasmuchifnotmorefromopeningtheireyestotheworldaroundthem. 1WhichofthefollowingcountryhasthemostForestKindergartens? A.TheU.S. B.Germany. C.TheU.K. D.Switzerland 2Whatisthepurposeofthefourthparagraph? A.Toanalysehowchildrenlearnsocially. B.Tocomparedifferentteachingapproaches C.Toshowhowchildrenlearnacademically D.Todescribehowactivechildrenareintheclass 3WhichmaybeseeninForestKindergartens? A.Childrenaredoinganexperimentwithchemicals. B.Teachersarewritingsomethingontheblackboard. C.Smartphonesarewidelyusedtohelpchildrenlearn• D.Everythinginnatureislikelytobeappliedtoteaching. 4Whatistheauthor'sattitudetoForestKindergartens? A.Negative. B.Doubtful. C.Positive. D.Uncertain.
30分Myfatherisaworkerinauthorityoverotherswhoworkinconstructionsites.WhenIwasyoungitwashewho1mesympathythroughmodeling.Ithasalwaysbeena2formeasIgrowup3otherconstructionworkerswhoworkwithhimcometoourhouseeverySaturdaybecausethatishetimewhenhewill4theirsalariesfortheweek. Iknowmyfatherassomeonewhoisaquietmanjust5everyonearoundhimself.Heissomeonewhois6whenitcomestodisciplinebutIhaveneverbeen7whenbeingraisedbyhim.MaybethatisbecauseIhaveseenhisgentlenessand8tousandtoothers.Sinceheisaworkerin9Ioftenseehimtalkingtotheconstructionworkerswhenevertheyhaveproblems.Heismorelikeafatherthana10tothem. Onedayhereturnedhometellingmethathewouldtreatmetodinnerbecausehehad11hissalary.Laterthatdayhisfriendafellowworkercametoourhousejusttotalktohimand12adviceastowherehecouldgotoseekassistanceforhis13child.Isawhowmyfatherlistenedand14hisfriend'sbackwhilehisfriendwas15.Whenhisfriendwasabouttogohomemyfathergothiswalletandgavehissalarytohim16only2000pesosinhiswallet. Iwasso17whenhedidthatbutso18thatmyfatherwas19togivealmostallofhissalarytohelphisfriendwithhischildinhospital.ItisalessonIwillalways20. 1A.asked B.gave C.taught D.designed 2A.routine B.balance C.tendency D.sign 3A.hearing B.seeing C.thinking D.smelling 4A.increase B.accept C.spend D.pay 5A.noticing B.kidding C.observing D.describing 6A.loose B.strict C.lovely D.humorous 7Athreatened B.loved C.hated D.envied 8A.sympathy B.bravery C.determination D.cruelty 9A.order B.rank C.charge D.turn 10A.doctor B.superior C.colleague D.engineer 11A.wasted B.asked C.reached D.received 12A.askfor B.lookfor C.headfor D.carefor 13A.naughty B.healthy C.sick D.happy 14A.pressed B.beat C.patted D.struck 15A.shouting B.crying Cthinking D.laughing 16A.saving B.donating C.giving D.leaving 17A.shocked B.scared C.frightened D.frustrated 18A.sad B.angry Cbitter Dproud 19A.mean B.unhappy C.surprised D.willing 20A.forget Btreasure C.neglect D.reject
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