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【探索发现】 如图1,△ABC是等边三角形,点D为BC边上一个动点,将△ACD绕点A逆时针旋转60°得到△AEF,连接CE.小明在探索这个问题时发现四边形ABCE是菱形. 小明是这样想的: ...
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△ABC中①若AB=BC=CA则△ABC是等边三角形②一个底角为60°的等腰三角形是等边三角形③顶
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如图已知△ABC为等边三角形D.为BC延长线上的一点CE平分∠ACDCE=BD求证△ADE为等边三角
在△ABC中①若AB=BC=CA则△ABC为等边三角形②若∠A=∠B=∠C则△ABC为等边三角形③有
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已知在△ABC中∠
=60°,如要判定△ABC是等边三角形, 还需添加一个条件.现有下面三种说法: ①如果添加条件“AB=AC”,那么△ABC是等边三角形; ②如果添加条件“∠
=∠
”,那么△ABC是等边三角形; ③如果添加条件“边AB,BC上的高相等”,那么△ABC是等边三角形. 其中正确的说法有 A.3个 B.2个C.1个
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△ABC中①若AB=BC=CA则△ABC是等边三角形②属于轴对称图形且有一个角为60°的三角形是等边
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关于等边三角形下列说法中错误的是
等边三角形中,各边都相等
等边三角形是特殊的等腰三角形
三个角都等于60°的三角形是等边三角形
有一个角为60°的等腰三角形不是等边三角形
1如图D是等边三角形△ABC边BA上任意一点D与AB不重合连接DC以DC为边在BC边上方作等边三角形
如图△ABC为等边三角形点D.E.F.分别在ABBCCA边上且△DEF是等边三角形求证△ADF≌△C
如图△ABC是等边三角形D.是AB边上的一点以CD为边作等边三角形CDE使点E.A.在直线DC的同侧
1如图1△ABC和△CDE都是等边三角形且B.C.D.三点共线联结ADBE相交于点P.求证BE=AD
如图△ABC是等边三角形D.是AB边上的一点以CD为边作等边三角形CDE使点E.A.在直线DC的同侧
下列推理中错误的是
∵∠A.=∠
=∠
,∴△ABC是等边三角形 B.∵AB=AC,且∠B.=∠C.,∴△ABC是等边三角形 C.∵∠A.=60°,∠B.=60°,∴△ABC是等边三角形
∵AB=AC,∠B.=60°,∴△ABC是等边三角形
如图△ABC是等边三角形D.是AB边上的一点以CD为边作等边三角形CDE使点E.A.在直线DC的同侧
等边三角形ABCP为等边三角形ABC所在平面上一点△PAB.△PCB与△PAC都是等腰三角形这样的点
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如图直线a∥b△ABC是等边三角形点A.在直线a上边BC在直线b上把△ABC沿BC方向平移BC的一半
如图△ABC是等边三角形D.是AB边上一点以CD为边作等边三角形CDE使点E.A.在直线DC的同侧连
如图在数轴上从原点A开始以AB=1为边长画等边三角形记为第一个等边三角形以BC=2为边长画等边三角
如图在数轴上从原点A开始以AB=1为边长画等边三角形记为第一个等边三角形以BC=2为边长画等边三角
如图在△ABC中分别以ACBC为边作等边三角形ACD和等边三角形BCE连接AEBD交于点O.则∠AO
已知如图延长△ABC的各边使得BF=ACAE=CD=AB顺次连接DEF得到△DEF为等边三角形.求证
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德国科学家们寻找一种可以减慢光速的金属﹣﹣镨.下列有关镨的说法错误的是
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逻辑推理是学好化学的重要思维方法下面是从小明同学学习笔记中摘录出来的一些推理你认为正确的一句是
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化学来源于生活化学与生活密切相关.下列说法不正确的是
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推理是化学学习的一种重要方法下列推理不正确的是
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目前有部分学生在做作业或考试时喜欢使用修正液涂改液经实验证明修正液中含有多种挥发性有害物质吸入后易引起头晕头痛严重者会呼吸困难抽搐.三氯乙烷CH3CCl3就是其中的一种.下面关于三氯乙烷的几种叙述正确的是
Thesalaryofworkinginasmallcityismuchlowerthaninbigcitiesthequalityoflifethereisprobablymuchhigher. A.since B.when C.as D.while
Neversaygoodbye WhenIwastenIwassuddenlyconfrontedwiththeseverepainofmovingfromtheonlyhomeIhadeverknown.Mywholelifebriefasitwashadbeenspentinthatbigoldhousedeeplyandthankfullytouchedbythelaughterandtearsoffourgenerations. WhenthefinaldaycameIrantotheheavenofthesmallbackporch走廊andsatalonetremblingastearswelledupfrommyheart.SuddenlyIfeltahandrestonmyshoulder.Ilookeduptoseemygrandfather.Itisn'teasyisitBilly?hesaidsoftlysittingdownonthestepsbesideme. GrandpaIrepliedthroughmytearsHowcanIeversaygoodbyetoyouandallmyfriends? Foramomenthejuststartedoffintotheappletrees.Goodbyeissuchasadwordhesaid.Itseemstoofinaltoocoldforfriendstouse.Weseemtohavesomanywaysofsayinggoodbyeandtheyallhaveonethingincommonsadness. Icontinuedtolookintohisface.Hegentlytookmyhandinhis.Comewithmemyfriendhewhispered. Wewalkedhandinhandtohisfavoriteplaceinthefrontyardwhereahugeredrosebushsatattractivelyalone. WhatdoyouseehereBilly?heasked. IlookedattheflowernotknowingwhattosayandthenansweredIseesomethingsoftandbeautifulGrandpa. Kneelinghepulledmeclose.Itisn'tjusttherosesthatarebeautifulBilly.It'sthatspecialplaceinyourheartthatmakesthemso. Hiseyesmetmineagain.BillyIplantedtheserosesalonglongtimeago﹣beforeyourmotherwasevenadream.Iputthemintothesoilthedaywhenmyfirstsonwasborn.Itwasmywayofsayingthank﹣youtoGod.Thatboy'snamewasBillyjustlikeyours.Iusedtowatchhimpickrosesforhismother. Isawmygrandfather'stears.Ihadneverseenhimcrybefore.Hisvoicebecamehoarse. Onedayaterriblewarcameandmysonlikesomanysonswentawaytofightagreatevil.HeandIwalkedtothetrainstationtogether﹣﹣﹣Threemonthslateratelegramcame.MysonhaddiedinsometinyvillageinItaly.AllIcouldthinkofwasthatthelastthingIsaidtohiminthislifewasgoodbye. Grandpaslowlystoodup.Don'teversaygoodbyeBilly.Don'tevergiveintothesadnessandtheloneliness.Iwantyoutorememberthejoyandthehappinessofthosetimeswhenyoufirstsaidhellotoafriend.Takethatspecialhelloandlockitawaywithinyou﹣inthatplaceinyourheartwheresummerisaregulartime.WhenyouandyourfriendsmustbepartedIwantyoutoreachdeepwithinyouandbringbackthatfirsthello. Ayearandhalflatermygrandfatherbecamegravelyill.Whenhereturnedfromseveralweeksinthehospitalhewantedhisbednexttothewindowwherehecouldseehisbelovedrosebush. ThefamilywassummonedandIreturnedtotheoldhouse.Itwasdecidedthattheoldestgrandchildrenwouldbeallowedtosaytheirgoodbyes.WhenitcametomyturnInotedhowtiredhelooked.Hiseyeswereclosedandbreathingwasslowandhard. Itookhishandasgentlyashehadoncetakenmine. HelloGrandpaIwhispered.Hiseyesslowlyopened. Hellomyfriendhesaidwithabriefsmile.HiseyesclosedagainandImovedon. Iwasstandingbyhisrosebushwhenanunclecametotellmethatmygrandfatherhaddied. RememberingGrandpa'swordsIreacheddeepwithinmeforthosespecialfeelingsthathadmadeupfriendship.SuddenlyandtrulyIknewwhathadmeantaboutneversayinggoodbye﹣refusetogiveintosadness. 1Theauthor'spurposeofwritingthispassageisto. A.conveyhissadnessandsorrowformovinghouse B.describethelaughterandtearsofthegenerationslivingtogether C.explaintherealmeaningofneversaygoodbye D.cherishthememoryofhisuncleandhisgrandfather 2Fromthelastparagraphwecaninferthat A.theauthor'sgrandfatherdied B.theauthordidn'tfeelsadabouthisgrandfather'sdeath C.theauthorhadadeepfriendshipwithhisgrandfatherratherthanlove D.theauthor'sgrandfatherlivesinhisheartforever 3ThefollowingstatementsbasedonthepassageareallrightEXCEPT A.theauthor'sunclehadbeeninthewarforlessthanhalfayear B.theauthorreturnedtotheoldhouseinordertolookafterhisgrandfather C.theauthor'sgrandfatherplantedtheroseswhentheauthor'sgrandmotherhadachild. D.theauthor'soldhousewasfilledwithlaughterandtears 4Whydidtheauthor'sgrandfathercrywhenwalkingwithhimintheyard? A.Hewassatisfiedwiththewholehappyfamily. B.Hewascontentwiththebloomingredroses. C.Therosesremindedhimofhisfirstsonwhodiedinthewar. D.Therosesbroughthimbacktothemomentwhensayinggoodbyetohisfirstson. 5Theunderlinedwordgravelyisclosestinmeaningto. A.gently B.seriously C.gracefully D.uncomfortably 6Whichofthefollowingcanbestdescribetheauthor'sgrandfatheraccordingtothepassage? A.Kindandstrong﹣willed B.Cautiousandenthusiastic C.Considerateandscholarly D.Humorousandsincere
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﹣Youshouldhavegottenheretwentyminutesago. ﹣I'msorrybuttheheavytrafficme. A.destroyed B.transported C.delayed D.confused
DebateCanstricterguncontrollawsdecreasetherateofcrimesinvolvingguns? Yesbecausewithfewerweaponsyougetfewercrimes. TakealookatthecrimeratesofcountriesliketheUnitedKingdom.TheircrimerateisverylowcomparedtoourshereintheUnitedStates.Justbysimplyputtingstricterlawsinplaceonwhocanownthemitwillgreatlyreducethecrimesinvolvingguns. Postedby5h4yGlory PastPractice Therewasanassaultweaponbanbackin1994underBillClinton.Shootingsandcrimedidnotgodownforthe10yearswhenthislawwasineffect.Criminalsdonotfollowrules.Thelawonlyaffectsthosewhotrytoobeythelawtoarmthemtoprotectthemselves. Postedbyjb1988 WakeupyouAmericans! It'shardlysurprisingthatAmericahasoneofthehighestgunrelatedmurderratesofallcountries!Andofcoursegunsdon'tkillpeoplebutthemorepeopleowngunstheeasieritistogetaccesstoonethehigherthechanceofpeopleusingittokillsomebodyis! InGermanywehavereallystrictgunlawsandonlyafewpeopleowngunsandobviouslywedon'tneedthem.There'snoreasonthatanormalcitizenwouldneedagun!Gunsaremadeforonereasononlykilling. Postedbycstephie13 Moreguncontrollawsfewershootings OnthesamedayastheSandyHooktragedyamaninChinaenteredaprimaryschoolwithaknifeandinjured22studentsonDecember14.Howevernobodywaskilled.Comparethattothe26studentsandteacherskilledatSandyHookinConnecticutwithapowerfulgun.Wemustlearnsomethingfromthistragedy. PostedbyJasonx986 Gunviolencegoesupwithmoreguncontrol Criminalwilltakeadvantageofthesituation.Theywilldowhatevertheywantandtakewhatevertheywantandkillwhoevergetsintheirway.Theywillgetgunsillegally.Crimeratesgoupasaresultofmoreguncontrolbecausecriminalsknowyoudon'thaveoneandtheywillkillyouastheylike.Banninggunsdoesn'tmakeanysense! Postedbyeebnflow 1AccordingtothefirstpostintheUnitedKingdom. A.buyinggunsisveryhard B.thereisnoguncontrollaws C.thecrimerateisrisingsharply D.thecrimerateishigherthanAmerica's 2Wecaninferthatjb1988. A.hasagun B.wasworkingunderBillClinton C.isinfavorofguncontrollaws D.isagainstguncontrollaws 3Whichofthefollowingdoescstephie13probablyagreewith? A.TheUSAhasoneofthehighestmurderratesintheworld. B.Themorepeopleowngunsthemorepeoplewillbekilledbythem. C.Peopleneedgunstoprotectthemselvesintimeofdanger. D.Gunsaremadetoprotectratherthankill. 4WhatdoweknowabouttheSandyHooktragedy? A.22studentswereinjuredwithoutanydeaths. B.26primarystudentswerekilledbyaknife. C.ThetragedytookplaceonDecember14inConnecticut. D.22studentsandteacherswerekilledbyapowerfulgun. 5Whichofthefollowingthinksthatgunsshouldnotbecontrolled? A.5h4yGlory B.cstephie13 C.Jasonx986 D.eebnflow
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Theywereabroadduringthemonthswhenwewerecarryingouttheinvestigationortheytoourhelp. A.wouldhavecome B.couldcome C.havecome D.hadcome
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手电筒是生活里一种手持式电子照明工具.请根据图示回答下列问题 1上述含有的金属元素有填元素符号属于有机合成材料的是填一种即可 2该塑料是选填“热塑性”或“热固性”塑料制品大量使用会引发的环境问题是. 3生活生产中使用合金十分广泛其原因可能是填一种即可.
ItisanewkindofrobotinventedbyChinesethatcanfeelpainwhenbeingusedinadentaltrainingcourse. A.one B.it C.that D.theone
中国最新战机歼﹣31使用了高强度耐高温的钛合金材料.钛元素的信息如图所示对图中信息解释不正确的是
Istillremembermymiddleschoollifeinthatsmalltown.IamtheninaschoolforstudentsfromTibet.Aswealllefthomeataearlyagewemetlotsofproblemsinourdailylife.Wehadtodothewashingcleaningandshoppingbyus.Howeverweseldomfeltlonelyorhelplessly.Weenjoyedourhappylife.Atweekendswewouldplaybasketballswaminthepoolorgoforapicnic.Wearelivedinabigfamily.Wetreatedeachotherbrothersandsisters.Ifanyoneofushadanydifficultywithhisstudiestheotherstudentwouldhelphimout.Ithasbeenfiveyearswhenwegraduatedbutthosememoriesareassweetasneverbefore.
小美从某粒子结构示意图如图中获取了下列信息其中错误的是
Mygrandmotherwasalwaysencouragingmetosetgoalsandworkhardtoachievethem.Shewouldtellmenottobeafollowerandnottoset1onwhatIcouldachieve.She2believedthattherewerenolimitsthatyoucould3whateveryouwanted.Iwouldneverforgetthefollowingstorythatsheoncetoldme.Afarmerwonfirst4atthecountryfairforhishugeradish小萝卜thatwastheexactshapeand5ofamilkbottle.Manywere6astohowthefarmerwasabletogrowthisradishthatwastheexactshapeofamilkbottle.7onegentlemanwentuptothefarmerandaskedthequestion.Thefarmerreplied'Itwas8.IgottheseedgrowingandthenIputitintothemilkbottle.Ithad9elsetogo.'Youcanusethisstoryasananalogy比喻tolife﹣ourlivesare10bythekindofsurroundingsweplaceourselvesinthepeoplethatweallowto11usandthegoalswegiveourselves.Ifweonly12andtakenoactionthenwegetnofurther.Butifwe13setagoalandtakeactionthenourlifetakesa14shape.Goalsandactionscanhelpusaccomplishmoreinayearthanwhatsomepeoplewillaccomplishinalifetime.Toprovethis15readthebiographiesof16peopleandyouwillseethatgoalsandactions17playedabigroleintheirsuccess.Rememberthe18ofMaryKayAshwhosaid'Don'tlimityourself.Manypeoplelimitthemselvestowhattheythinktheycando.Youcango19yourmindletsyou.Whatyoubelieverememberyoucanachieve.'Insummarydon'tputyourselfinabottleinotherwordsmoveoutofwhatis20andsecureifyouwanttomoveforward.1A.expectations B.rules C.limits D.lines2A.truly B.naturally C.tightly D.partly3A.win B.grasp C.realize D.achieve4A.price B.prize C.position D.award5A.size B.length C.weight D.height6A.doubtful B.worried C.anxious D.curious7A.Immediately B.Gradually C.Finally D.Actually8A.strange B.easy C.funny D.secret9A.nowhere B.everywhere C.somewhere D.anywhere10A.shaped B.formed C.controlled D.improved11A.understand B.help C.influence D.contact12A.dream B.refuse C.doubt D.change13A.struggle B.refuse C.continue D.plan14A.beautiful B.different C.solid D.clear15A.truth B.lesson C.point D.evidence16A.successful B.brave C.friendly D.careful17A.asusual B.aboveall C.atall D.infact18A.case B.wisdom C.thought D.speech19A.asif B.incase C.asfaras D.aslongas20A.comfortable B.valuable C.ordinary D.boring
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