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如图，在多面体ABCDEF中，平面ADE∥平面BCF，四边形ACFE为平面四边形． （1）求证：CF∥平面ABE； （2）若四边形ABCD为菱形，∠BAD＝60°，AB＝BE＝DE＝2，，求三棱...
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高三下学期数学《》真题及答案
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如图多面体ABCDEF中底面ABCD是菱形∠BCD＝60°四边形BDEF是正方形且DE⊥平面ABC
如图在多面体ABCDEF中四边形ABCD是矩形AB∥EF∠EAB=90ºAB=2AD=AE=EF=1
如图在多面体ABCDEF中四边形ABCD是正方形AB＝2EF＝2EF∥ABEF⊥FB∠BFC＝90°
2016年·龙岩一模如图在多面体ABCDEF中四边形ABCD为矩形△ADE△BCF均为等边三角形E
在如图所示的多面体中四边形ABCD是菱形ED∥FBED⊥平面ABCDAD=BD=2BF=2DE=2.
如图在五面体ABCDEF中四边形ABCD是边长为2的正方形EF∥平面ABCDEF=1FB=FC∠BF
如图在多面体ABCDEF中四边形ABCD为平行四边形平面ADE⊥平面CDEF∠ADE=60°DE∥
已知如图G.78所示的多面体中四边形ABCD是菱形四边形BDEF是矩形ED⊥平面ABCD∠BAD＝
如图在多面体ABCDEF中AB＝2EFEF∥ABH.为BC的中点.求证FH∥平面EDB.
如图在多面体ABCDEF中底面ABCD是边长为2的菱形四边形BDEF是矩形平面BDEF⊥平面ABCD
如图所示多面体中AD⊥平面PDCABCD为平行四边形E为AD的中点F为线段BP上一点∠CDP=120
如图在多面体ABCDEF中四边形ABCD是菱形ACBD相交于点OEF∥ABAB=2EF平面BCF⊥平
如图在多面体ABCDEF中平面ADEF⊥平面ABCD．四边形ADEF为正方形四边形ABCD为梯形且
如图在多面体ABCDEF中底面ABCD是边长为2的菱形四边形BDEF是矩形平面BDEF⊥平面ABCD
12.00分如图在多面体ABCDEF中四边形ABCD是梯形AD∥BCBAD=90°CF⊥平面ABC
如图多面体ABCDEF中四边形ABCD是矩形EF∥ADFA⊥面ABCDAB=AF=EF=1AD=2A
如图在多面体ABCDEF中四边形ABCD是矩形AB//EF∠EAB=90°AB=2AD=AE=EF=
如图在多面体ABCDEF中已知四边形ABCD是边长为1的正方形且△ADE△BCF均为正三角形EF∥A
在如图所示的多面体中已知正三棱柱的所有棱长均为2四边形是菱形.Ⅰ求证平面平面.Ⅱ求该多面体的体积.
如图在多面体ABCDEF中底面ABCD是边长为2的正方形四边形BDEF是矩形平面BDEF平面ABCD
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如图在△ABC中AD平分∠BAC交BC于DDE⊥AB于点E若S△ACD=7DE=2则AC的长是
如图所示底端装有电子阀门的圆柱形容器放在水平桌面上容器中装有适量的水一木块漂浮在水面上控制阀门使容器中相同时间内流出的水量相等．下列表示木块下表面处水的压强p1容器对桌面的压强p2木块的重力势能Ep和木块所受的浮力大小F随时间t变化的关系图象中可能正确的是
小雯用自制的水凸透镜当向水凸透镜里注水时焦距变小抽水时焦距变大来探究“凸透镜成像规律”． 1如图甲所示让一束平行于主光轴的光射向水凸透镜在光屏上出现一个最小最亮的光斑则此水凸透镜的焦距为cm． 2小雯将蜡烛水凸透镜和光屏调整至图乙所示的位置时光屏上出现清晰的烛焰像此像的性质是倒立的实像小雯接着在蜡烛和光屏位置都不变的情况下将水凸透镜移至光具座cm刻度处再次得到清晰的烛焰像．然后小雯利用注射器从水凸透镜中向外抽少许水光屏上原来清晰的像变得模糊不清小雯要想重新得到清晰的烛焰像在蜡烛和水凸透镜的位置都不变的情况下应将光屏向选填“远离”或“靠近”水凸透镜的方向移动．
关于安全用电下列说法正确的是
计算xy4÷-xy2=
热敏电阻的阻值随温度的改变而改变且对温度很敏感．热敏电阻的阻值在特定温度时会发生急剧变化它在笔记本电脑自动控制系统等方面有多种用途．如甲电路图电源电压是7伏当闭合开关S电压表示数如乙图所示．热敏电阻的电流随电压变化I﹣U关系如丙图所示．求 1热敏电阻两端的电压 2电阻R的值 3电阻R上消耗的功率．
同学们在探究小灯泡的亮度与功率的关系实验中所用电源电压为6V灯泡的额定电压U0＝3.8V额定功率在1﹣1.5W的范围内．1按图甲所示的电路图请你用笔画线代替导线将图乙的电路补充完整．2小杜同学在实验过程中将滑动变阻器的滑片P缓慢向B端移动小灯泡的实际功率将选填变大变小或不变同时观察到小灯泡的亮度将变选填亮或暗．3另一组的小张同学在实验过程中发现电流表电压表示数如图丙所示此时电流表的示数是A电压表的示数是V经分析造成这种现象的原因是．4小张同学重新调整电路连接后继续探究小灯泡在额定功率时的亮度但发现无法准确读出额定电压他用第3小问中所测得数据先算出灯泡的电阻RL再根据P0＝计算灯泡的额定功率．按此方案算出灯的额定功率比真实值偏选填大或小原因是．
某空调铭牌上标有“220V2000W”字样它的额定功率为正常工作2小时消耗的电能是度消耗的电能可用表来测量．
用如图所示滑轮组在15s内将重1000N的物体匀速上升了3m人用的拉力F为400N不计绳重和摩擦力．求 1动滑轮的重 2绳子自由端拉力F做的功 3滑轮组的机械效率． 4若将重物的重力增加200N后用这滑轮组将重物匀速提高相同的高度该滑轮组的机械效率是多少结果百分数保留一位小数
如图是探究电流通过导体时产生热的多少与哪些因素有关的实验装置．三个密闭容器中的电阻如图三个容器串联在其中一个容器的外部将一个电阻和这个容器内的电阻并联通电后观察三个U形管中液面高度的变化．实验现象表明
HungryforHomeIfmylifewerea1Iwouldfast﹣forwardthroughseniorhigh．Mysenioryearswere2．LikeeveryjuniorhighkidIwas3withwhoIwasandhowIwould4inlife．ItriedandfailedinanumberofthingsIwantedtoexcelinsportsbuthadnotyet5howtoIrememberbeing6bymostofmypeersandbeingcutfromthebasketballteamand7toplayfootball．TobelovedandacceptedseemedtomeatthetimesomethingIcouldnever8achieve．DuringthattimeIwentthroughthecafeterialineandatealonefeelingunlovedand9．OnedayI10thatIhadnoonetoeatwith．MomsaidtomeIfyouwantyoucancomehomefor11．Assoonashebell12atnoonandIlefttheschoolandranhomethatdaymymomsatacrossthe13forabout15minutesandlookedatmeandlistenedtomeandthree14laterIstillrememberthosetimeswith15．Shejustpaidattentiontome．InowknowthatIdidn'tneedmy16filledasmuchasIneededmyemotionalfueltankrefilled．Ijustneededa17placeofwarmacceptanceforafewminutesaday．NowyouknowalittlemoreabouthowI18home．Homeisaplacewhereyoudon'thaveto19aloneandeat．Homeisaplacewherepeopledon't20youandavoidyou．1A．book B．movie C．quiz D．choice2A．amazing B．unforgettable C．painful D．tasteless3A．struggling B．travelling C．discussing D．improving4A．makemymark B．drawmyattention C．makeacontribution D．drawaconclusion5A．brokenup B．turneddown C．gotover D．figuredout6A．admired B．impressed C．rejected D．mixed7A．desiring B．failing C．meaning D．hesitating8A．inallmylife B．inthisrespect C．onaregularbasis D．ontheaverage9A．unemployed B．unnoticed C．unaffected D．uncovered10A．commented B．admitted C．complained D．answered11A．lunch B．fun C．sale D．luck12A．rang B．knocked C．kicked D．repeated13A．room B．phone C．table D．street14A．days B．decades C．weeks D．minutes15A．care B．caution C．excitement D．fondness16A．soul B．stomach C．heart D．eye17A．lonely B．heavy C．steady D．friendly18A．own B．see C．paint D．attract19A．dash B．laugh C．sit D．talk20A．ignore B．hate C．judge D．attend
先化简再求值[x+yx-y-x-y2+2yx-y]÷4y其中x=1y=-3
Ahybridelectricvehicle混合动力车orHEVisavehicledrivenbythecombinationofpetrolengineandelectricmotor．TerrencehasbeendrivingaHEVforfiveyears．Hereallydoesn'tunderstandwhymorepeoplearen'tacceptingthem．Iprobablyspendabout﹩7adayonpetrolthetaxidrivertoldnews．com．au．InhispreviousconventionalvehicleTerrencesaidhewasspendingupto﹩30adayonpetrolmeaninghesavesalmost﹩6000everyyear． TheToyotaspokesmansaidthiswasquiteahighsavingandofficialtestsestimate估计anaveragedriverwouldonlysaveabout33percentofftheircurrentbill．Thismeansadriverpaying﹩30adayonpetrolwouldseetheirbilldroptoabout﹩20usingthehybrid．Ataxidriverthatdrivesinbuilt﹣upareasandspendslittletimeonhighwayswillnoticeahigherfuelsavinghesaid．Lowspeedsallowtheelectricmotorstobeusedmoreandthepetrolengineusedless． WhilesomepeopleareskepticalabouthowreliablehybridsareTerrencesaidhehadneverrunoutofpower．HisCamrycostabout﹩34000andsoafterfiveyearsit'snearlypaidforitself．Forcabdriversit'sarealadvantagebecauseofthecost﹣effectivenesshesaid．Terrencehasnocomplaintsaboutthecar．Iloveitthecalmandquietnessofitthesimplicityofit﹣youjustjumpinandgo．Themaintenance保养isreallylow．Buttheonlydifficultyisfindingsomeonetoservicethecarastherearenotmanyexperiencedmechanics机修工． Terrencesaidit'sextraordinarythatmoredriversaren'tbuyingmorehybridelectricvehiclesandthatgovernmentsarenotencouragingthismore．Ithinkpeoplehaveaviewthatyouhavetoplugitinwhichisnottrue．Alackofinformationaboutthecarsmaybestoppingpeoplefromtakingtheplunge．It'snotpromotedatallforthepublictounderstand﹣it'ssimplifyingtheactualowningofacar﹣youdon'thavetodosomanythingstoownitandrunitit'sjustsomuchsimpler．Whywouldn'tthegovernmentpromotesuchathing 1Howmuchdoesanaveragedriversaveeachdaybydrivingahybrid A．﹩30 B．﹩20 C．﹩10 D．﹩7 2Terrence'sproblemwithhisHEVatthemomentisaboutthe． A．speed B．power C．price D．service 3WhensayingextraordinaryTerrencethinksitis． A．understandable B．wonderful C．doubtful D．unbelievable 4WhatdoesTerrencethinkpreventsthepopularityofhybridcars A．Thedifficultyinservicingthecar． B．Therestrictionofthegovernment． C．ThelackofinformationaboutHEV． D．Theinconveniencewithchargingthecar．
在等腰直角三角形ABC中∠BAC=90°AB=AC直线MN过点A且MN∥BC过点B作Rt△BDE∠BDE=90°且点D在直线MN上不与点A重合1如图1DE与AC交于点P求证BD=DP2在图2中DE与CA延长线交于点PBD=DP是否成立如果成立请给予证明如果不成立请说明理由
小明在观察碘锤中的物态变化之前查阅资料得知酒精灯外焰的温度约为800℃．碘的熔点为113.7℃．我们选用图方式加热理由是．
下列运算中正确的是A．a23=a5 B．a2·a3=a5 C．a2+a3=a5 D．a6÷a2=a3
7.5分FivedaysaweekVictorIbarraandhisfriendSandyNorseridebicyclesthroughNorthBrooklyncollectingfoodwastefromrestaurantscoffeeshopsandothersmallbusinessesandpackingitintoplastictubsonatrailer拖车pulledbyhisbike．AndeverySundayafternoonneighborhoodresidentschoppedtheirfoodwastefirstlywaitingforVictorIbarraandSandyNorse'sarrivaltocollectthestaff．Thesehouseholdwastecontainsmorewholeappleswholetomatoesandwholebunchesofcabbagesthancommercialwastedoeswhilecatlitterbonesanddisposablecupsbowlsandplatesarenotaccepted． In2016theyevenfoundedBKROTanonprofitcollectingandcompostingoperationtocontinuetheircareers．AtBKROTfoodwasteismixedwithwoodchipsandsawdust锯末thenmovedoveraperiodofweeksthroughaseriesofwoodenbinsthesizeofwashingmachines．Bythetimeitreachesthefinalbinit'sblackandbug﹣coveredandunrecognizableasformerfood．Theresultingmassthecompostissoldinlocalstoresordirectlytoindividuals．SomebodycamefromStatenIslandyesterdayandtookalotNorsesaidbutmostofitgoestonearbyurbanfarmsandcommunitygardens． Somefarmersandmanycitizensfollowtheirexamplesbeginningtoturntorunningtheirfarmsandgardenswithoutusinganychemicals．Totheirdelighttheyfeelthatthismakesthesoilintheirfieldsricherinmineralsandsomorefertile．BKRotisbecomingpopularwithagoal﹣﹣﹣togrowgoodfoodandavoiddamagingtheenvironmentorpeople'shealth． 1Howisthecompostmadefrom A．Firstcombinedwithsawdustmovedandthenrots． B．Firstmovedprocessedandthensold． C．Firstcollectedpackedandthensenttofarms． D．Firstchoppedmovedandthendeliveredtoindividuals． 2Whatcanwelearnaboutthecompost A．Compostingoperationcanonlybeconductedbyprofessionals． B．Notallthehouseholdfoodwastecanbeprocessedintothecompost． C．Thecompostmaybeonlycomefromthehouseholdwaste． D．Theresultingmesswillbepackedintoawoodenbintillitrots． 3Whichofthefollowingisthebesttitleforthetext A．CollectingFoodWasteAttractsMorePeople B．VictorIbarraandSandyNorseGoGreen C．FoodWasteCanBeTurnedintoTreasure D．FarmersWillBeBlessedwiththeCompost
7.5分Boys&GirlsClubsofKingCountyisproudtoannounceCassyamemberofWallingfordBoys&GirlsClubhaswonthetitleofourYouthoftheYear． Intotal12extraordinaryteensfromClubsacrossthecountycompetedforthetitle．EachcandidatewasjudgedonthefollowingLeadershipandservicetotheirClubandcommunitytheirlifegoalsandvaluesmoralcharacteracademicsuccessandtheirpublicspeakingskillsduringaninterview． Cassywalkedawaywiththewinningtitleanda﹩2000educationscholarship．ShesaidWhentherewasnooneelsetoreachouttoIknewIcouldturntothestaffattheBoys&GirlsClub．WithouttheClubIwouldn'thavehadthestrengthtocontinuemystudieswhilemyfamilywashomeless．IhavecometothinkoftheBoys&GirlsClubasnotonlyaplacetogotoafterschoolbutashelterandahomeawayfromhome． Cassyisincrediblyhard﹣workinganddrivensaidMeghanSweetDirectorofWallingfordBoys&GirlsClub．Shewon'tletherchallengesgetinthewayofhersuccess．TheClubhasprovidedherwithasecondhomewhilesheinturnhashelpedmaketheClubthetypeofwarmwelcomingplacewestrivetoprovideforallourmembers．TheworldneedsmoreyoungwomenlikeCassywhoprovethatanyonewhoisgivenaplaceandanopportunitytodeveloptheirpotentialcanbecomeacommunityleader． Cassyvaluesthevoicesofindividualswhoarehomeless．Sheherselfhasexperiencedhomelessnessandwantstosharerealstoriesofthehomelesstopromotepeople'sunderstandingofthem．Sheco﹣foundedastudentorganizationwheresheandotherstudentsinterviewhomelessindividualsandsharetheirstoriesonaFacebookpagecalledTheUnheardVoicesofSeattle． 1WhatdoweknowaboutthecompetitionCassyenteredfor A．Itisintendedforordinaryteens． B．Itoffersthecandidatesscholarship． C．Ithascertainstandardsforthewinner． D．ItisheldbyWallingfordBoys&GirlsClub． 2Cassyisasuccessfulexampleofateenwhoknowshowto． A．shareherrealstories B．developpeople'spotentials C．repaythecommunityforitshelp D．interviewhomelessindividuals 3Whatisthepassagemainlytalkingabout A．TheUnheardVoicesofSeattle． B．ThewinneroftheYouthoftheYear． C．Boys&GirlsClubsofKingCounty． D．Themovingstoriesofhomelesskids．
3分电热膜是一种新型的电热器件电热膜是在绝缘的聚酯薄膜表面经过特殊工艺加工形成的一条条薄的导电墨线导电墨线两端与金属导线相连形成网状结构其内部结构如图甲所示．电热膜取暖器工作时室内空气温度升高是通过方式增加空气内能的．将此电热膜接入电路正常工作时金属导线中AB处电流分别为IA和IB则IAIB选填＞＜或＝导电墨线电阻随温度变化的关系如图乙所示电热膜不会因厚度不均而出现局部过热的现象原因是．
IworkforMrs．Rileyaneighty﹣year﹣oldneighbor．I1groceriesforheratthesupermarketandsometimesIdustand2herapartment．Thebestpart3istakingcareofSamhercanary金丝雀．Hesingsallthetimeandisalwayscheerful．I'mgoingtobuy4．ButIdon'thaveenoughmoneyyet．5soon． LastThursdayIranupstairstoMrs．Riley's．Shewasinbed．Youcan't6formeanymoregirl．MrsRileysaidIcan't7topayyou．Ifelt8tomystomach．HowwouldIfindanotherjobAtdinnerIcouldn'teat．MomsaidIfeel9forherCarla．She'ssoaloneupthere．LeaningoverMomgavemeahugandsaidI'mgladwe10eachother．ThatnightIcouldn't11．IkeptthinkingaboutMrs．Riley．Howwouldshegetthingsfromthestore12me ThenextdayIranupstairs．Mrs．Rileywas13inbed．WhenIaskedwhatshewantedthatdayMrs．Riley14meforaminuteandthentoldme．WhenTgotbackMrs．Rileywatchedme15．Afterawhileshespoke16Ican'tpayyouI'llgiveyouSam．Mybreathcaughtinmythroat．Icouldn't17it．ButifItookSamMrs．Rileywouldbeallalone．ThenIsighedIcan'ttakeSam．He18you．Andyoudon'thavetopayme．Shereachedoutandpattedmyarm．You'reagood19Carla．Mrs．Rileysaid．Ifeltalumpinmythroat．Whosaysfriendshavetobeyourown20 1A．buy B．deliver C．pack D．carry 2A．protect B．sweep C．furnish D．share 3A．instead B．therefore C．though D．otherwise 4A．one B．it C．that D．this 5A．Hopefully B．Curiously C．Occasionally D．Gradually 6A．talk B．pay C．work D．wait 7A．bother B．expect C．offer D．afford 8A．sick B．cautious C．nervous D．guilty 9A．sorry B．embarrassed C．ashamed D．strange 10A．like B．have C．help D．connect 11A．think B．understand C．sleep D．speak 12A．for B．with C．after D．without 13A．still B．just C．even D．ever 14A．listenedto B．lookedat C．checkedon D．reachedfor 15A．onpurpose B．withpride C．insilence D．forpermission 16A．Before B．Unless C．Until D．Since 17A．bear B．believe C．ignore D．make 18A．looksafter B．belongsto C．worksfor D．dependson 19A．assistant B．neighbor C．daughter D．friend 20A．sex B．mind C．age D．family
计算2x-y2·2x+y2
图1是小丽探究动能大小与速度关系时的实验场景斜面上有两平行轨道将两小球①②从轨道上由静止释放与放置在水平木板上的两个相同木块①②发生碰撞两个木块初始位置到斜面底端的距离相等． 1为完成实验应使两个质量的小球从轨道上高度由静止释放均选填“相同”或“不同” 2由图1场景可知碰撞木块前瞬间小球的动能较大两木块通过AB两点处所受的滑动摩擦力大小分别为fAfB则fAfB滑行中木块的动能转化成能 3图2是某次实验的场景将两小球从图中EF处静止释放最终木块①从水平木板的右端滑出小丽用质量更大的木块③替换木块①后继续此次实验将两小球仍从图中EF处由静止释放木块③未滑出木板小丽的实验改进有一处遗漏它是．
已知x-m2=nx2-6x+p则m+n+p的值为
如图所示小球在A点由静止开始释放向右侧摆动．B点是小球摆动的最低点C点是小球摆到右侧最高点且AC两点到B点的竖直距离hA＞hC．在小球从B点摆动到C点的过程中下列说法正确的是
7.5分 1WhatcanweknowaboutMarriottDetroitSouthfield A．Itisdesignedspeciallyforbusinessmen． B．Ithaswell﹣developedtraffictoothercities． C．Itisquiteclosetolocalattractions． D．Itisthecheapestofthethreehotels． 2Whatcanwelearnfromthethreeadvertisements A．YoumaybringpetsintoResidenceInnMilford． B．ResidenceInnMilfordislocatedinNewYork C．MarriottDetroitSouthfieldisbuiltinsideapark． D．SmokingisallowedinComfortSuitesKodak． 3Ifyouwanttotakeexerciseandgoclimbingaftersettlingdownyoumaychoose． A．NewHavenhotel B．MarriottDetroitSouthfield C．ResidenceInnMilford D．ComfortSuitesKodak
计算1998×1.51997×-11999=
下列科技应用中说法错误的是
下列估计值中最接近实际的是
假如你是某国际学校的学生李华在刚结束的中学生英语演讲比赛中获得了笫一名．准备比赛期间你得到了外教James的指导和帮助．请你裉据以下要点提示给外教James写一封邮件． 要点提示 1．告知获奖的消息 2．感谢外教的帮助． 注意 1．词数80左右 2．可适当增加细节以使行文连贯．
如图所示一束光线经平面镜反射后过凸透镜的焦点F射向凸透镜请在图中画出射向平面镜的入射光线和经凸透镜后的折射光线并标出入射角的度数．
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