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已知a,b,c分别为△ABC内角A,B,C的对边,acosB+b=c. (1)求A; (2)若a=,△ABC的面积为,求△ABC的周长.
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高二下学期数学《》真题及答案
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Igrewupwithoutafather.Wellsortof.Myparentsdivorced离婚inthe1960﹩whenIwasasmallchildandIstayedwithmymotherinLosAngeles.MyfatherremarriedandmovedtoasmallsuburbofAtlanta.ForonemonthoutoftheyearinthesummerIwouldflybackandspendtimewithmydadsoIhadafatherattimes. FurtherIhadaseriesofstepfatherswhorangedfromwonderfulguystoalcoholicstodangerousindividuals.HavinglivedthroughsuchexperiencesIfinditamusingwhenpeoplesaythatchildrenreallyneedafatherinthehome.WellifheisagoodfatherandagoodmanthenIagreecompletely.Ifheisnotthenthechildmightactuallybebetteroffwithouthim.Wedon'tjustneedfathers﹣weneedgoodfathers. IfeelitfairtosayIendedupaverysuccessfuladultatleastthat'swhatpeopletellme.SohowdidIdoit?Ithinkitstartedwithmehavingabitofachiponmyshoulder.Normallythisisnotagoodthingbutinmycaseitwasrocketfuelforachievement.Nothavingafatherinmylifegavemesomethingtoproveanditmotivated激励meinanI'llshowyouway. Ialsotriedveryhardevenasalittleboytobeself﹣sufficient.AndthatmeansIdidnotrelyuponmyparentsexcepttotheextentnecessary.ThiskindofindependenceIbelieveishighlymissedinthisageofhighlymanagedchildrenwithhelicopterparentshovering盘旋abovethemconstantly. IalsothinkIneverwantednothavingafatherinmylifetobeanexcuseformyself.WemakeandallowexcusesconstantlythesedaysbutIjustneverfeltthatfeelingsorryformyselfwasgoingtogetmeanywhereIthinkifchildrencanadoptsuchmindsetsearlyintheirlivesitcanbehelpful. 1Accordingtothefirsttwoparagraphstheauthorthinks. A.hisfatherisabadone B.nobodyneedsafather C.childrenneedagoodfather D.childrenreallyneedafather 2Howdidtheauthorendupaverysuccessfuladult? A.Hewasveryintelligent B.Hemadeexcuseforhimself C.Hewasmotivatedbyafather D.Hewasveryindependentandtriedveryhard 3Whatdoestheunderlinedwordself﹣sufficientmeaninparagraph4? A.Abletodependonmyself. B.Abletodressmyselfveryquickly. C.Abletoplaybymyself. D.Abletoworkonmyown. 4Howcanwedescribetheauthorfromthepassage? A.Friendlycleverandwarm﹣hearted. B.Cleverdeterminedandindependent. C.Motivatedhard﹣workingandindependent. D.Motivatedhard﹣workingandwarm﹣hearted.
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NA表示阿伏加德罗常数的值.俗名为“臭碱”的硫化钠广泛应用于治金染料皮革电镀等工业.硫化钠的一种制备方法是Na2SO4+2CNa2S+2CO2↑.下列有关说法正确的是
ItwasalongtimesinceIhadseenmyparentslasttime.LastSaturdayIdrovealongwaytovisitthem1neitherofthemwasathome.SoIwaitedpatientlyattheirhome2theirreturn.Notseeingthemmademereally3. AsIwaswalkingaroundtheirbedroomI4littleremindersofthem.SomeChristmasgiftswerestill5inboxes.Therewere6onthewallwhichIguessmusthavea7meaningtothem.Whattookmybreathawaywasseeingmydad'semblems徽章fromhismilitarysereofourcountry8hewasyoung.Myfathernever9tousabouttheKoreanWars.AsIlookedatthoseemblemshanging10withallthephotosthathetreasuresI11thatthiswasanimportantpartofhislifebutIneverspent12intalkingwithhimaboutthem.Thephotosofmymomwithherclose13mademerealizeherlifebeforeshewasmymom.Ihadbeenso14runningmybusinesstoraisemyownfamilythatI15thechancetoknowabouttheirpastandexperience. Wesometimesdon'trealizesomethingis16forusuntilwehavelostitsoit'snottoolateforustotalktoourparentsabouttheirpast.Iamwritingmystoryto17everyonewhoisfortunatetostillhavetheirparents18toinvestsometimetolearnaboutthem.Iamgratefultohave19ofmyparents.SoIstillhavetimetotalkwiththem.Ihopethatreaderswill20frommystoryandfindthetimetotalkaboutthosethingsintheirlifethatmeansomuchtotheirparents. 1A.and B.or C.but D.so 2A.to B.for C.of D.in 3A.frightened B.embarrassed C.excited D.upset 4A.sought B.saw C.needed D.took 5A.covered B.folded C.hidden D.kept 6A.SantaClaus B.familyphotos C.familytrees D.oldclothes 7A.simple B.special C.past D.real 8A.if B.until C.though D.when 9A.showed B.explained C.talked D.referred 10A.finally B.clearly C.openly D.proudly 11A.realized B.declared C.admitted D.promised 12A.courage B.chance C.time D.energy 13A.students B.teachers C.friends D.children 14A.strict B.eager C.blind D.busy 15A.rejected B.missed C.delayed D.avoided 16A.hopeful B.original C.careful D.important 17A.warn B.demand C.require D.encourage 18A.away B.around C.awake D.alone 19A.both B.neither C.either D.one 20A.make B.change C.benefit D.Recover
OxfordandCambridgehavenowdecidedtoremovethewordsCAN'TandIMPOSSIBLEfromtheirdictionary.JessicaCoxbornin1983inArizonaistheworld'sfirstlicensedarmlesspilot. ThegirlfromTucsonArizonagottheSportPilotcertificatelatelyandbecamethefirstpilotlicensedtoflyusingonlyherfeet.JessicaCoxwasbornwithoutarmsbutthathasonlystoppedherfromdoingonethingusingthewordcan't. CoxgraduatedfromtheUniversityofArizonain2005withabachelor'sdegreeinpsychologyandaminorincommunications.Coxhasnotusedprostheticarmssincesheturned14.Usingherfeetasmostpeopleusetheirhandssheisableamongotherthingstodriveanunmodifiedcarwithanunrestrictedlicensetotypeonakeyboardat25wordsperminuteandtoputinandremovehercontactlenses. JessicaCoxflewinasingleengineairplaneforthefirsttimeviaWrightFlightin2005.Coxearnedherpilot'scertificateonOctober102008afterthreeyearsoftrainingandisqualifiedtoflyalight﹣sportaircrafttoaltitudeof10000feet. She'sagoodpilot.She'srocksolidsaidParrishTraweek42theflyinginstructoratSanManuel'sRayBlairAirport.ParrishTraweekrunsPCAircraftMaintenanceandFlightServicesandhastrainedmanypilotssomeofwhomdidn'tcomeclosetoCox'sabilities. Doctorsneverlearnedwhyshewasbornwithoutarmsbutshefiguredoutearlythatshedidn'twanttouseprostheticdevices.SothenexttimeyouarereadytotellyourselfIcan'tpossibly…rememberthisamazingyoungwomanandchangeyourvocabulary. 1Whatcanwelearnfromthefirstparagraphs? A.OxfordandCambridgefeltalittledisappointed. B.Noarmlesspeoplehadgotapilotcertificatebefore. C.JessicaCoxwasn'tallowedtousethewordcan't. D.Thewordcan'twoulddisappearfromtheEnglishdictionary. 2WhatdoyouthinkofJessicaCox? A.Sheisacleverandbravegirl. B.Sheispositiveanddetermined. C.Sheisindeedapoorlyeducatedgirl. D.Sheonlytakesinterestinaircraft. 3WhatdoestheunderlinedwordprostheticmeaninParagraph3? A.artificial B.damaged C.unusual D.abnormal 4AftergraduatingfromuniversityJessicaCox. A.sufferedfailurewhensearchingforjobs. B.madeastarttotaketrainingtobecomeapilot C.decidedtouseherfeetasmostpeopleusehands. D.triedherbesttotakecareofherselfinherdailylife.
Doyouusuallyfeelyou'reworkinghardbutstillcan'treachyourstudygoals?Herearesomequicktipstohelpyoustudybetter. ♦Studywithapartneroringroups Ratherthanlivinginacavewithyournoseinthebooksalldaygrabafriendfromyourclassandstudywithhim.1 ♦Stepintoyourteacher'sshoes AskyourselfIfIweretheteacherwhatwouldIputonthetest?Youhaveprobablyexperiencedalotofyourteacher'stestsandquizzesbynow.2Teachershavespecifictypesofinformationthattheywantyoutolearn.Thestructureisusuallythesame. ♦Paintpicturesonthepaper Youcanbuildyourknowledgestructureintheformofpictures.It'shardertoremembereachpieceofapuzzleindividuallythanitistorecallthecompletedpicture.3 ♦4 Ahungrybrainisanineffectiveone.Yourbrainneedsthepropernutrientstokeepitgoing.Becauseofthiswhatyoueatanddrinkalsoplaysahugeroleinhowsharpyourbrainis.Healthyfoodsprovidenutrientstoyourbraincellstokeepthemenergized. ♦Takebreakstorelaxyourbrain Yourbrainislikeamuscle.Itcanbealsotiredifyouoverworkit5Ifyoudividestudyinginto15to30minutesblockswithquickbreaksinbetweenyourbrainwillfeelrefreshedgratefulandreadyforthenextchallengeyouthrowat. A.Feedyourbrainfromtimetotime. B.Itneedsexercisetomakeitstronger. C.Relaxyourbrainbyeatinganddrinking. D.You'dbetterlearnfromthemforthenexttest. E.It'snecessarytohavealongholidayandhavenicefood. F.Findwaystoconnectwhatyouarelearningtoreallifeortootherconcepts. G.Groupstudyinghelpsyoutoengageandprocesstheinformationmoredeeply.
ItisgoodmforanArabtostandclosetohisfriendswhentheyaretalking.
AccordingtonewresearchfromtheUniversityofCambridgeinEnglandsheepareabletorecognizehumanfacesfromphotographs. Thefarmanimalswhoaresocialandhavelargebrainswerepreviouslyknowntobeabletorecognizeoneanotheraswellasfamiliarhumans.Howevertheirabilitytorecognizehumanfacesfromphotosaloneisnovel. TherecentstudytheresultsofwhichwerepublishedinthejournalRoyalSocietyOpenScience.ShowthewoollycreaturescouldbetrainedtorecognizestillimagesofhumanfacesincludingthoseofformerPresidentBarackObamaandactressEmmaWatson. Initially最初thesheepweretrainedtoapproachcertainimagesbybeinggivenfoodrewards.Latertheywereabletorecognizetheimageforwhichtheyhadbeenrewarded.Thesheepcouldevenrecognizeimagesoffacesshownatananglethoughtheirabilitytodosodeclinedbyabout15percent﹣thesamerateatwhichahuman'sabilitytoperformthesametaskdeclines. AnyonewhohasspenttimeworkingwithsheepwillknowthattheyareintelligentindividualanimalswhoareabletorecognizetheirhandlerssaidProfessorJennyMortonwholedtheCambridgestudy.We'veshownwithourstudythatsheephaveadvancedface﹣recognitionabilitiescomparablewiththoseofhumansandmonkeys. RecognizingfacesisoneofthemostimportantsocialskillsforhumanbeingandsomedisordersofthebrainincludingHuntington'sdiseaseaffectthisability. Sheeparelong﹣livedandhavebrainsthataresimilarinsizeandcomplexitytothoseofsomemonkeys.ThatmeanstheycanbeusefulmodelstohelpusunderstanddisordersofthebrainsuchasHuntington'sdiseasethatdevelopoveralongtimeandaffectcognitiveabilities.OurstudygivesusanotherwaytomonitorhowtheseabilitieschangeMortonsaid. 1Accordingtothenewresearchwhat'sunusualaboutsheep? A.Theyhavelargebrains. B.Theycanrecognizetheirowners. C.Theycantellanimalsfromhumans. D.Theycanrecognizehumanfacesfromphotograph. 2Howdidtheresearcherstrainthesheep? A.Byguidingthemtofollowtheirhandlers. B.Byshowingphotosofhumansandmonkeysbyturns. C.Bygivingfoodrewards. D.Byshowingphotosoffamouspeople. 3Whatcanbeinferredfromthepassage? A.Sheephaveahigherface﹣recognitionabilitythanmonkeys. B.Thenewdiscoveryisbeneficialtothestudyofcognitiveabilitychanges. C.Thesheep'sface﹣recognitionabilitysaysthesamewhenshownphotosatanyangle. D.Thesheep'sface﹣recognitionabilitymaypreventsomedisordersofthebrain. 4What'sthebesttitleofthepassage? A.ANewdiscoveryaboutSheep. B.HowSheepRecognizeEachOther. C.AWonderfulScientist. D.TheLifeofSheep.
假设你是李华你的英国网友Jack正在学习汉语他在信中询问你如何提高汉语写作能力.请你用英语给他写封信就如何提高写作能力给他提些建议. 内容要点如下 1.多读别人的文章Chinesearticles 2.多写多练 3.不要害怕出错. 4.其他 注意1.词数100左右2.可适当增加细节以使行文连贯.
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