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在△ABC中,角A,B,C所对的边分别为a,b,c,bsinB+csinC=a(+sinA) (1)求A的大小; (2)若a=,B=,求△ABC的面积
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高三下学期数学《》真题及答案
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在△ABC中已知角
,
,
所对的边分别为a,b,c,且a=3,c=8,B.=60°,则△ABC的周长是( ) A.17,B.19,C.16,
18
三角形ABC中角A.BC所对的边分别为abc已知求边C.及面积S.
在△ABC中角ABC所对应的边分别为abc若a=csinA则的最大值为.
在△ABC中角A.B.C.所对的边分别为abc设向量p=a+cbq=b-ac-a若p∥q求角C.的大
已知在△ABC中角A.B.C.所对的边分别为1求△ABC中的最大角2求角C.的正弦值
在△ABC中角A.B.C.所对的边分别为abc.若A.B.C.构成等差数列那么角B.等于.
在△ABC中角A.B.C.所对的边分别为abc已知1求角A.的大小2若a+b=4c=3求△ABC的面
在△ABC中角ABC所对的边分别为abc如果a=2c=A=30°那么△ABC的面积等于.
在△ABC中已知角ABC所对的边分别为abc.若asinA.-sinB.=csinC.-bsinB.
在△ABC中角A.B.C.所对的边分别为abc设S.为△ABC的面积满足则角C.的大小为
.△ABC中角A.B.C.所对的边分别为abca=5b=7B.=60°则c=__________.
在周长为16的三角形ABC中AB=6AB所对的边分别为ab则abcosC的取值范围是.
在△ABC中角A.B.C.所对的边分别为abc若abc成等比数列则角B.的取值范围为.
.在△ABC中角A.B.C.所对的边分别为abc且b2+c2=a2+bc则角A.的大小为.
在△ABC中abc分别为角A.B.C.所对的边若a=2bcosC则此三角形一定是________三角
在△ABC中角A.B.C.所对的边分别为abc若
在△ABC中角A.B.C.所对的边分别为abc且b2+c2=a2+bc则角A.的大小为
在锐角△ABC中abc分别为角A.B.C.所对的边且a=2csinA.角C.=________.
在△ABC中角A.B.C.所对的边分别为abc若a=1∠B=450△ABC的面积s=2.1求边b的长
在锐角△ABC中abc分别为角A.B.C.所对的边且a=2csinA则角C.=________.
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WhenEdisonwassevenEdison'sfamilymovedfromOhiotoMichiganafterhisfathergotajobthere.Becauseofhearingproblemshehaddifficulty1followthelessonsandoftenranawayfromschool.Howeverhe2usethetimetoreadbooksandsetupalaboratoryinhishome.Butthesmellfromhislaboratorywasoftensostrong3hismotherhadtostophimfrom4carryoutanymoreexperimentsathome. Attheageof16EdisongotajobontheGrandTrunkRailway.Therehemadeuseofausedcar5hislaboratory.Duringthattimehe6successdevelopedsomethingthatcouldsendmessages.By1869Edison'sinventionsintelegraphywerewidelyaccepted7madehimdecidetoleavethejobandbecomeafulltime8invent.Edison'smostwellknowninventionsincludedtheelectriclightbulbmicrophonesandsoon. Edisondiedat9ageof84onOctober181931.AtthetimeofhisdeathhewasstilldoingexperimentsinhislaboratoryinWestOrangeNewJersey.Heclearlyenjoyedhisworkandlivedlifetothe10full.
阅读下面短文根据所给情节进行续写使之构成一个完整的故事.OncewhenIwasateenagermyfatherandIwerestandinginlinetobuyticketsforthecircus.Finallytherewasonlyonefamilybetweenusandtheticketcounter.Thisfamilymadeabigimpressiononme.Therewereeightchildrenallprobablyundertheageoftwelve.Youcouldtelltheydidn'thavealotofmoney.Theirclotheswerenotexpensivebuttheywereclean.Thechildrenwerewell﹣behavedallofthemstandinginlinetwo﹣by﹣twobehindtheirparentsholdinghands.Theywereexcitedlytalkingabouttheclownselephantsandotheractstheywouldseethatnightwiththeirbrothersorsistersinalowvoice.Onecouldsensetheyhadneverbeentothecircusbefore.Itpromisedtobeahighlightoftheiryounglives.Thefatherandmotherwereattheheadofthelinestandingproudastheycouldbe.Themotherwasholdingherhusband'shandlookingupathimasiftosay'Youaremyknightinshiningarmor.'Hewassmilingandrespondinginpridelookingbackatherasiftosay'Yougotthatright'.Theticketladyaskedthefatherhowmanyticketshewanted.Heproudlyresponded'Pleaseletmebuyeightchildren'sticketsandtwoadultticketssoIcantakemyfamilytothecircus.'Theticketladygavetheprice.Theman'swifeletgoofhishandloweredherheadandherlipsbegantoshake.Thefatherleanedalittlecloserandasked'Howmuchdidyousay?'Theticketladytoldhimthepriceagain.Themanobviouslydidn'thaveenoughmoney.Howwashesupposedtoturnandtellhiseightchildrenthathedidn'thaveenoughmoneytotakethemtothecircus?ActuallywewerenotwealthyinonesensesoIunderstoodhowthekidswouldfeel.Ifeltsorryforthem.注意1.所续写短文的词数应为150左右2.至少使用5个短文中标有下划线的关键词语3.续写部分分为两段每段的开头语已为你写好4.续写完成后请用下划线标出你所使用的关键词语.Paragraph1Seeingwhatwasgoingonmydadseemedtohaveanidea.Paragraph2ThenmyfatherandIwentbackhome.
PrepareYourselfforaBetterTOEFLScore TheTOEFListhemostwidelyusedlameassessmentexamforAmericancollegesoruniversities.ManyforeignstudentsworryabouttakingtheTOEFLbecauseitisessentialtomeettheirgoals.1Butalowtestscorewilllimittheirchoicesforfinancialaidandadmissiontotopschools.SohowtoprepareyourselfforabetterTOEFLscore? Whatwillyoufocuson? PlanwhenyouwilltaketheTOEFL.Ifpossibleregistertotakethetestevenifthedateisseveralmonthsfromnow.Thiswillgiveyouagoodreasontostudy.Takeasampletestonlineorfromatestpreparationbooktofindoutwhereyouneedtoimprovethemost.2Thiswillhelpyoutoplanyourstudiestodeveloptheskillsyouneedtogetabetterscore. 3 TheEducationalTestingServicewebsitehasafreeonlinecoursetohelpyoupreparefortheTOEFL.Therearealsosamplepreparationquestions.ApartfromansweringthosequestionstrytosurroundyourselfwithEnglish.ListentostoriesonVOA'sLearningEnglishwebsite.WatchmovieswhereEnglishisspoken.ReadEnglish﹣languagenewspaperstokeepupwithnewwordsthatrelatetocurrenteventsandtechnology. Whenwillyoustudy? 4Butifyourpracticetestscoreismorethan20pointsbelowyourgoalyoumayneedtoimproveyouroverallEnglishabilityandthatmaytakeyears.Togetagoodscoreyouneedtosetasidetimetostudysetgoalsandmeasureyourprogress. TherealgoalofthetestistomeasurehowwellastudentcancommunicateinanEnglish﹣speakingclassroom.5 A.Howwillyoustudy? B.Donotdependoninformaladviceortricks. C.Goodmarksonthetestwillopenmanydoors. D.Doyoudowellinreadingbutnotsowellinlistening? E.Exportssaythatyoushouldstudyforatleasttwomonthsbeforetakingthetest. F.ExposeyourselftoEnglishonadailybasisandimprovementissuretofollow G.ATOEFLscoremaybenecessarytogetastudentvisatoanEnglish﹣speakingcountry.
阅读下面短文根据其内容写一篇60词左右的内容概要.Paperlessofficewasfirstcoinedin1975.Fourdecadeslaterwe'restillchasingthepaperlessofficedream.Takethefinancialindustryforexample﹣itisoneoftheslowerindustriestohugdigitaltransformation.Manyfinancialinstitutionstodaystillsendouttradeconformationsbymail.Icantellyoufromfirsthandexperiencethatgoingpaperlessisbynomeansimpossible.TheCentricDigitalofficeisapaperlessworkenvironmentwherealltheofficeoperationsgodigitalwhichhasamazedourbusinesspartners.Actuallycompaniesneedtostressthebenefitsofadigitalcultureforcommunications.Goingpaperlesscansavetimeandmoney.Youcouldsaygoodbyetocostlyrepairsofficesupplyorderswastedemployeetimeandsoon.Besidesforbiddingpaperintheofficeforcesinformationtobe100%digitalwhereyoucanmakeendlessamountsofbackups备份whicheasilyincreasetransparency透明.Nottomentiontoptalentswanttoworkfordigitalcompanies.Youmightthinkthesecrettoapaperlesscompanyispurelytechnology.Wellnotreally.ThankstoproductslikeiPadssmartphonesandcloudservicestheabilitytogopaperlessishighlyaccessible.Yetevenwithallthistechnologycompaniescontinuetorelyonpaper.It'snotbecausetheydon'thaveaccesstothetechnologybutbecausethey'relackingthepoliticsorganizationalstructureandstrongdesiretochange.Inordertogopaperlesscompaniesneedtochangethewaytheythinkandoperate.Thedecisionneedstobemadeandcriedoutandeveryoneneedstoworktogethertomakeit.Yesthepaperlessofficehasbeenaverylongtimeinthemaking一butitnolongerhastobe.Withnumerousamountsofsoftwareservicesappsandtechnologyavailabletodaytheonlythingweneedtodoistomakethedecisiontogopaperlessandseeitthrough.
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如果食物链上各营养级均以生物个体的数量来表示并以食物链起点的生物个体数作底层来绘制数量金字塔则只有两个营养级的夏季草原生态系统假设第一营养级是牧草第二营养级是羊和森林生态系统假设第一营养级是乔木第二营养级是昆虫数量金字塔的形状最可能是
假设在特定环境中某种动物基因型为BB和Bb的受精卵均可发育成个体基因型为bb的受精卵全部死亡.现有基因型均为Bb的该动物1000对每对含有1个父本和1个母本在这种环境中若每对亲本只形成一个受精卵则理论上该群体的子一代中BBBbbb个体的数目依次为
阅读下面短文根据所给情节进行续写使之构成一个完整的故事.Iwasdoingabigclean﹣uprecentlyandmykidswerehelpingwhenmysonFreddocameacrossaknottedhandkerchiefwithanolddarkbrowncoininside.'MumcanIhavethis?CanIplaywiththiscoin'heasked.Itookonelookandwasimmediatelytransportedtoanothertime.In1991therewasatimewhenmyfriendandIworkedinabackwardAfricancountryNigerhitbysandstormsandburningheat.ThereweremanythingsIfounddifficultaboutthisplace﹣﹣theclimateandbeggarsweremybiggestheadaches.SoafterfinishingfivemonthsofnursingworktherewemovedontoworkatahealthclinicinneighbouringcountryBurkinaFaso.'It'smuchgreenerinBurkina.EventheCoketastesbetter'thelocalsassuredus.Yetthefactwasquitetheopposite.ArrivingbytaxiatourdestinationinBurkinawebegantounload.Iwasreachingformylargerpieceofluggagewhenoutofthedarknessamotorbikewithtwomenapproachedslowly.Withoutwarningoneofthemengrabbedmydaypackasthemotorbikesweptcloseby.Withinsecondsthepairwereoutofsightswallowedupbythenight.Withmypassportmoneytraveller'schequesallinthebagIwasindeeptrouble.Howfrustrating!AllIwantedwastoleavethishellhole!ThenwalkingthroughBurkina'sstreetsonedayIwasstoppedbyanoldwomanwhothrustherhandinmyface.'Cadeau'gift'inFrench!Cadeau!'shecried.I'dhadenough!Iwasextremelytiredofthecountryitspovertyitsthievestheheatthedustandeverything!ItoldherangrilyandfirmlyinFrench'Ihaveno'Cadeau'.Ihavenomoney.AthiefstoleallmymoneytwoweeksagoandnowIcan'tgetoutofyourcountry.Icannotgiveyouanything.NOTHING!'Thebeggarwomanlistenedattentively.Tomygreatsurpriseafterhearingmywordsshegaveabroadsmile.注意1.所续写的短文的词数应为150词左右2.应使用5个以上短文中标有下划线的关键词语3.续写部分分为两段每段的开头语已为你写好4.续写完成后请用下划线标出你所使用的关键词语.Shereachedintothepocketofherdress.TherewasaslighttouchonmyhandlookingdownIsawmysonlookingatmecurious.
7.5分Ascientistworkingatherlabbenchandasix﹣month﹣oldbabyplayingwithhisfoodmightseemtohavelittleincommon.Afterallthescientistisengagedinseriousresearchtouncovertheverynatureofthephysicalworldandthebabyiswelljustplaying…right?Perhapsbutsomedevelopmentalpsychologists心理学家havearguedthatthisplayismorelikeascientificinvestigationthanonemightthink. Takeacloserlookatthebabyplayingatthetable.Eachtimethebowlofriceispushedoverthetableedgeitfallstotheground﹣andintheprocessitbringsoutimportantevidenceabouthowphysicalobjectsinteract相互作用bowlsofricedonotfloatinmid﹣airbutrequiresupporttoremainstable.Itislikelythatbabiesarenotbornknowingthisbasicfactoftheuniversenoraretheyeverclearlytaughtit.Insteadbabiesmayformanunderstandingofobjectsupportthroughrepeatedexperimentsandthenbuildonthisknowledgetolearnevenmoreabouthowobjectsinteract.Thoughtheirrangesandtoolsdifferthebaby'sinvestigationandthescientist'sexperimentappeartosharethesameaimtolearnaboutthenaturalworldoverallapproachgatheringdirectevidencefromtheworldandlogicaremyobservationswhatIexpected?. Somepsychologistssuggestthatyoungchildrenlearnaboutmorethanjustthephysicalworldinthisway﹣thattheyinvestigatehumanpsychologyandtherulesoflanguageusingsimilarmeans.ForexampleitmayonlybethroughrepeatedexperimentsevidencegatheringandfinallyoverturningatheorythatababywillcometoaccepttheideathatotherpeoplecanhavedifferentviewsanddesiresfromwhatheorshehasforexampleunlikethechildMommyactuallydoesn'tlikeDovechocolate. Viewingchildhooddevelopmentasascientificinvestigationthrowslightonhowchildrenlearnbutitalsooffersaninspiringlookatscienceandscientists.Whydoyoungchildrenandscientistsseemtobesomuchalike?Psychologistshavesuggestedthatscienceasaneffort﹣thedesiretoexploreexplainandunderstandourworld﹣issimplysomethingthatcomesfromourbabyhood.Perhapsevolution进化providedhumanbabieswithcuriosityandanaturaldrivetoexplaintheirworldsandadultscientistssimplymakeuseofthesamedrivethatservedthemaschildren.Thesamecognitive认知的systemsthatmakeyoungchildrenfeelgoodaboutfiguringsomethingoutmayhavebeenadoptedbyadultscientists.AssomepsychologistsputitItisnotthatchildrenarelittlescientistsbutthatscientistsarebigchildren. 1Accordingtosomedevelopmentalpsychologists. A.ababy'splayisnothingmorethanagame. B.scientificresearchintobabies'gamesispossible C.thenatureofbabies'playhasbeenthoroughlyinvestigated D.ababy'splayissomehowsimilartoascientist'sexperiment 2WelearnfromParagraph2that. A.scientistsandbabiesseemtoobservetheworlddifferently B.scientistsandbabiesofteninteractwitheachother C.babiesarebornwiththeknowledgeofobjectsupport D.babiesseemtocollectevidencejustasscientistsdo 3Childrenmaylearntherulesoflanguageby. A.exploringthephysicalworld B.investigatinghumanpsychology C.repeatingtheirownexperiments D.observingtheirparents'behaviors
阅读下面短文根据其内容写一篇60词左右的内容概要.You'resittingonthetrainhomeandthepersonoppositeyouyawns打哈欠.Suddenlyyou'reyawningwithhimthoughyou'renottired.Thisphenomenonconfusedscientistsforyearsuntilarecentstudyfoundthatpeopletendtosympathize同情withfellowhumans.Supportingthisclaimwasthediscoverythatthosechildrenwhowereunabletoformnormalemotionaltieswithothersdidnotexperiencecontagious有传染性的yawningwhichshowedthathumanscommunicateregularlywithoutwords.HugoD.Critchleyaneuroscientisthasconductedanexperimentrecentlywhichwillprovethathappinessandsadnesscanspreadlikethecommoncold.AccordingtoCritchleyourmindandbodyareinconstantexchangeabouthowwe'refeeling.'Emotionsarecloselylinkedwithstatesofinternal体内的responses'heexplained.'Therearealsomorevisiblechangesinourgesturesandfacialexpressions.Whenwe'reinagroupthesesignalscanspreadtoanotherperson.Forexamplethere'stheobvioustendencytosmilewhensmiledatandtherearelessobviouschangesthatreflectemotionsofsurpriseangerorsadnesssuchasachangeinourheartrateandbloodpressure.'HugoD.Critchleyfurtherexplained'Ourbodiessynchronize同步andwhenweliketheotherpersonweevercopyhisbehaviour.Nexttimeyouchatwithafriendtakenoteofhowyou'resitting﹣it'sprettylikelythatyouwillbethesame.Scientistsbelieveit'sourwayoftellingeachotherthatwe'repartners.Throughbodylanguagehumansgiveeachotherverysubtlebutclearsignalsthatshowemotions.'Sowhatlessonscanwelearnfromthis?'Spendtimewithhappypeople﹣otherwiseyourhealthcouldsuffer'saidCritchley.'Whenwe'resadourbodygoesintofightorflightmode.Butwhenwe'rehappyourbodyworksnormallyandwefeelrelaxedandpositive.Sowelookbrightourskinglowswefeelhealthyanditaffectseveryonearoundus.'
Reutersreportedthatthescientist'seffortsgotrewardedwhenthetwinchickenswereclonedinthelabafteryearsofexperiments.Thisbreakthrough1possibleenabledpeopletobringtheiradoredpetsbacktolife.2itbotheredhimfromtimetotimethattheirhealthwasinpoorconditionbecausetheywere3abletoresistillnesses.Thisdrawback4casthimdown.Merelytwoweekslatertheclonesandtheircarrierdied5struckfrustrationintohisheart.Heretiredbeforeheattainedhisambitionandbecameamemberofanoperachorustorelievehisdepression. Shortlyafterwardsthemediapublishedaconservative6argueobjectingtocloningowingtomoralproblemsandsuggestedcommercialprofitsfromcloning7forbid. When8interviewthescientiststaredatthedecorationsontheceilingthinkingforawhileandthensaidI'mnotinfavour9anyarbitraryassumptionbut10undertakecloningdoesdifferfromthestraightforwardprocedureofmakingloafsoutofflour.Untilweaccumulateenoughexactknowledgeanypracticeisinvainandisboundtofail.
环境中的内分泌干扰物是与某种性激素分子结构类似的物质对小鼠的内分泌功能会产生不良影响.回答下列问题. 1通常机体内性激素在血液中的浓度与靶细胞受体结合并起作用后会. 2与初级精母细胞相比精细胞的染色体数目减半原因是在减数分裂过程中. 3小鼠睾丸分泌的激素通过体液发挥调节作用.与神经调节相比体液调节的特点有答出4点即可.
SoonafterIgotofftheship1fillwithtradesmenfromsmallboatsIwasstoppedbyamansellingdiamondrings.Ireallyspentsometime2getridofhim.Thenanotherman3approachmewithsomeexpensivewatchesandpens4arousedmyinterest. CanIhavealookatthepens?Iaskedthemanwhoimmediatelyhanded5tomeandsaidit'sapenofhighqualitysir.It's6£50butyoucanhaveitfor£30asaspecialfavor.YetIstillthoughtitwastooexpensivesobetweenustherewasan7argueabouttheprice.FinallyIgotthepenfor£5.Whatabargain!Onlyonetenthoftheoriginalprice!Iwaswild8joywithoutnoticingthesellerdisappearintothecrowdquickly.ThenIwentbacktotheship9extremepleased.ButthisstorydidnothaveahappyendingIcouldn'tfillthepenwithinkanditjustdidn'twork!Evenfivepounds10betoomuch!TherewasnodoubtthatIhadbeenfooledbytheseller.Nowonderhehadbeeninsuchahurrytogetaway!
A.Getinvolvedinstudentactivities B.Yourvoiceisactuallysuperimportant C.Thereisasignificantincreaseofopportunities D.Stayinactivecommunicationwithyourfriends E.Getsmartaboutthepeoplewhoyouspendyourtimewith F.Yourmajordoesnotmatterasmuchinyourfirstyearofcollege FiveThingsNobodyToldMeaboutCollege AsItypethisIaminmyuniversitydormroom.AyearagowhenIwasawaitingtoheartheresultsofmycollegeapplicationsIoftenwenttowebsitesforsometypeofinsiderlookonwhatcollegewouldbelike.Howeverthere'sonlysomuchthatprepbookswebsitesandolderfriendscanteach.Herearethetop5thingsnobodytoldmeaboutcollege 1 Nobodyenteringauniversityknowsexactlywhattheywanttostudy.Iftheytellyouotherwisethey'relyingandwillprobablychangewhattheywanttopursuewithinthefirstquarterofattendance.DuringmyfirstquarteratUniversityofCaliforniaRiversideUCRIthoughtthatIwantedtostudyPoliticalSciencewithitsfocusonInternationalAffairssothat'swhatIappliedfor.HoweveronceIworkedwithstatewideandlocalgovernmentIrealizedthatabetterfitformewouldbePublicPolicyandnowIamintheprocessofchangingmyarea. 2 Incollegetherearesomanygoodchancesforyoutomeetyourexpectations.Howeverthereisaveryimportantdifferencebetweenwantingtodosomethingandapplyingforsomething.Inorderforyoutotakefulladvantageoftheconferencesresearchinternships实习andfellowshipsthatyouruniversityoffersapply!Stepintoyouracademicadvisor'sofficeintroduceyourselfandbeginmakingthevaluableconnectionsthatarenecessarytohelpduringtherestofyourcollegecareer.Greatthingshappenwhenyoustepoutofyourcomfortzoneandyouwouldbesurprisedonhowmanychancesexistifyoujustask. 3 Collegeiswhereyoumeetyourbridesmaidsgroomsmenneighborsandpotentialbosses.Therelationshipsyoudevelopnowwillprobablybelinkedtotheonesyouvaluelatersobewiseaboutthepeoplewhoyouinvestyourselfin.Youareonlyonepersonandyoudonothavetimetowasteonpeoplewhowouldrathercausedramaormessupwithyourpurpose.Surroundyourselfwithupliftingindividualswhochallengeyoutobebetterwhilelovingyouforwhoyouareandbepatienttothepeoplewhoarethecompleteoppositeofthatdescription. 4 Asafirst﹣yearIwasafraidtomakeanynoisetowardscampusissuesthatInoticed.ItwasnotuntilIbecameinvolvedinstudentgovernmentthatIgainedtheconfidencetohandleprojectsthatIcreatedwiththehelpofASUCROfficeofthePresident.DuringmyfirstquarterIspokedirectlytotheChancellor校长askinghimforsupporttowardsmyinitiatives提议metwiththeViceChancellorsandcooperatedwithmyteachingassistantstobeginmyundergraduateresearchprotect.Nothinggoodwillhappenwhenyouaresilent. 5 Atmyhighschooltherewereaboutonlyfouractiveclubandorganizationsthatstudentscouldbeapartof.ImaginemysurprisewhenIsteppedfootontoUCR'scampuswhereover400organizationsexistrangingfrompoliticalorganizationstokarateclub.Youarenotpayingallofyourtuition学费tomerelygotoclassstudypasstestsandgraduate.Makesomethingworthyoutofyourexperience.Createstoriesthatyouwillwanttotellyourgrandchildrenoneday.Itallbeginsherebysigninguptojoinanorganization.
某种甘蓝的叶色有绿色和紫色.已知叶色受2对独立遗传的基因A/a和B/b控制只含隐性基因的个体表现隐性性状其他基因型的个体均表现显性性状.某小组用绿叶甘蓝和紫叶甘蓝进行了一系列实验. 实验①让绿叶甘蓝甲的植株进行自交子代都是绿叶 实验②让甲植株与紫叶甘蓝乙植株杂交子代个体中绿叶紫叶=13 回答下列问题. 1甘蓝叶色中隐性性状是实验①中甲植株的基因型为. 2实验②中乙植株的基因型为子代中有种基因型. 3用另一紫叶甘蓝丙植株与甲植株杂交若杂交子代中紫叶和绿叶的分离比为11则丙植株所有可能的基因型是若杂交子代均为紫叶则丙植株所有可能的基因型是若杂交子代均为紫叶且让该子代自交自交子代中紫叶与绿叶的分离比为151则丙植株的基因型为.
植物组织培养技术在科学研究和生产实践中得到了广泛的应用.回答下列问题. 1植物微型繁殖是植物繁殖的一种途径.与常规的种子繁殖方法相比这种微型繁殖技术的特点有答出2点即可. 2通过组织培养技术可把植物组织细胞培养成胚状体再通过人工种皮人工薄膜包装得到人工种子如图所示这种人工种子在适宜条件下可萌发生长.人工种皮具备透气性的作用是.人工胚乳能够为胚状体生长提供所需的物质因此应含有植物激素和等几类物质. 3用脱毒苗进行繁殖可以减少作物感染病毒.为了获得脱毒苗可以选取植物的进行组织培养. 4植物组织培养技术可与基因工程技术相结合获得转基因植株.将含有目的基因的细胞培养成一个完整植株的基本程序是用流程图表示.
动物初次接受某种抗原刺激能引发初次免疫应答再次接受同种抗原刺激能引发再次免疫应答.某研究小组取若干只实验小鼠分成四组进行实验实验分组及处理见下表. 回答下列问题. 1为确定ABCD四组小鼠是否有免疫应答发生应检测的免疫活性物质是填“抗体”或“抗原”. 2再次注射抗原后上述四组小鼠中能出现再次免疫应答的组是.初次注射抗原后机体能产生记忆细胞再次注射同种抗原后这些记忆细胞能够. 3A组小鼠再次注射抗原甲一段时间后取血清血清中加入抗原甲后会出现沉淀产生这种现象的原因是. 4若小鼠发生过敏反应过敏反应的特点一般有答出2点即可.
阅读下面短文根据所给情节进行续写使之构成一个完整的故事.WhenIwastenyearsoldIlivedwithmyfamilyinasmallhouseinruralSouthJersey.IoftenaccompaniedmymothertotheA&Ptobuygroceries.WithoutacarwewalkedandIwouldhelphercarrythebags.Mymotherhadtoshopeverycarefullyasshewasawaitressandhersalarybarelysustained勉强维持us.OnedaywhileshewasweighingpricesapromotionaldisplayfortheWorldBookEncyclopediacaughtmyeye.Thevolumeswerebeautifullycream﹣colored.VolumeIwasninety﹣ninecentswithaten﹣dollarpurchase.AllIcouldthinkofwhileshoppingwasthebook.Istoodattheregister收银台withmymotherholdingmybreathasthecashierranguptheitems.Itcametooverelevendollars.Mymotherproducedafivesomesinglesandahandfulofchange.AsshewascountingoutthemoneyIsomehowfoundthecouragetoaskfortheencyclopedia百科全书.'Couldwegetone?'Isaidshowingherthedisplay.'It'sonlyninety﹣ninecents.'Ididnotunderstandmymother'sincreasinganxietyshedidnothaveenoughchangeandhadtosacrificealargecanofpeastopaytheamount.'NotnowPatricia'shesaidsternly.Todayisnotagoodday.'Ipackedthegroceriesandfollowedherhomeupset.ThenextSaturdaymymothergavemeadollarandsentmetotheA&Palone.Twoquartsofmilkandaloafofbread﹣﹣﹣that'swhatadollarin1957.IwentstraighttotheWorldBookdisplay.TherewasonlyonefirstvolumeleftwhichIplacedinmycart购物车.Ididn'tneedacartbuttookonesoIcouldreadasIwentupanddowntheaisles.AlotoftimewentbyandIknewIhadtoleavebutIcouldn'tbeartopartwiththebook.WithnodetectiveinsightIimpulsively冲动地putitinsidemyshirtandzippedupmyjacket.IwasatallskinnykidandIamcertaintheshapeofthebookwasobvious.Paragraph1MyheartbeatingrapidlyIheadedfortheregister.Paragraph2Backhome.ItoldmymotherwhatIhadpromisedthedetective.
Forsomepeoplewalkingorrunningoutdoorsisaeatwaytoworkout.Whatmaynotbesopleasantisseeingtrashallovertheground.Wellsomepeoplearedoingsomethingaboutit.Theyareplogging! PloggingbeganinSweden.ThenamecombinetheSwedishwordplockawhichmeanstopickupandthewordjoggingwhichmeanstorunslowly.ASwedishmannamedErikstartedthemovementin2016.OntheWorldEnvironmentDaywebsiteEriksaysthathemovedtoStockholmfromasmallcommunityinnorthernSweden.Eachdayhewouldridehisbiketowork.Concernedabouttheamountoftrashandlitterhesaweachdayonhiswaytoworkhetookmattersintohisownhands. PloggingbythattermmayhaveofficiallybeguninSweden.Butmanypeoplewhoexerciseoutdoorshavebeendoingthisforyears.TakeJeffHorowitzforexample.HeisapersonaltrainerinWashingtonD.C.Heoftenpicksuptrashwhilerunningoutside.Heevenasturneditintoagamehewilltrytopickupthetrashwithoutstopping.Ididn'tknowitwasathingreally.Thisisjustmypersonalethics道德标准whereIgoforarunandifIhappentoseeapieceofgarbagelyingaroundandit'swithinreach﹣﹣﹣itisakindofalittletestformetoseeifIcangrabitandthrowitinanearrashcanwithoutstopping.AndthatwayIthinkitgivesmealittleexerciseandalittlefocusformyrun.Andithelpscleanuptheneighborhoodheannounced. Todayloggingisanofficialactivityonethatisbecomingincreasinglypopular.Citiesaroundtheworldnowholdloggingevents.Iwouldjusthopepeoplewouldthinktwicebeforedroppingagarbageontheround.Wehavecontainers…seemsoneveryblock.Soit'seasytoputyourgarbageinthetrashcans.Ijustthinkpeopleshouldthinkaboutitalittlebitmore.Idohopeonedaytherewillnotbeaneedforlogging.saidaninterviewee. 1Whichofthefollowingcanreplacetheunderlinedphrasetookmattersintohisownhands? A.calledonpeopletojoinhim B.appealedtopeopletogogreen. C.begantopickupthetrash. D.hadthecollectedtrashrecycled. 2LikeJeffHorowitzloggingtomanypeoplehasbecomeaanact. A.automatic. B.irresistible. C.arbitrary D.temporary 3WhatistheideathatLoggingeventsaremeanttopromote? A.loggingistrulybeneficial B.Trashcansshouldbewithinreach C.Litteringisnotacceptable. D.Communitiesshouldbekeptclean. 4Whatcanbeasuitabletitleforthepassage? A.NewExerciseEnjoysunbelievablepopularity B.NewExerciseTrendAlsoHelpsEnvironment C.Plogging﹣aFashionableWaytoclearwaste D.Plogging﹣anExerciseOriginatinginSweden
若将n粒玉米种子置于__中使其萌发得到n株黄化苗.那么与萌发前的这n粒干种子相比这些黄化苗的有机物总量和呼吸强度表现为
培养胡萝卜根组织可获得试管苗获得试管苗的过程如图所示. 回答下列问题. 1利用胡萝卜根段进行组织培养可以形成试管苗.用分化的植物细胞可以培养成完整的植株这是因为植物细胞具有. 2步骤③切取的组织块中要带有形成层原因是. 3从步骤⑤到步骤⑥需要更换新的培养基其原因是.在新的培养基上愈伤组织通过细胞的过程最终可形成试管苗. 4步骤⑥要进行照光培养其作用是. 5经组织培养得到的植株一般可保持原品种的这种繁殖方式属于繁殖.
7.5分I'dliketosharealittlestorywithyouaboutsomethingthathappenedwhenIwasfour.Irememberitclearly.Ourlovingfamilydogwasnearingtheendofhislife.Myfatherpickedhimupandputhiminalittlebedwehadmadeforhim.Ourdogmycompanionwhomwehadcaredforbitmyfatherwhenheattemptedtohelphim.Howcouldhe?Why?Icouldn'tunderstandit.Ididn'tlikehimanymore. Ihadn'tthoughtaboutthatstoryforalongtimebutsomethingthathappenedlastweekbroughtitbacktome.Iwenttospeakwithafriend.WhenIknockedonthedoorImetinaninstantanangrylookandafewharsh尖刻的words.Whenthedoorwasslammed砰地关上inmyfaceIstoodthereshockedandinarushIwasremindedofmydogbitmyfather20yearsagoorso.Whatbroughtthatstorybackwasthatsamefeelingofbetrayal. Bothstoriestaughtmesomethingthenextday.YouseewhenIgotupinthemorningandwastoldmydoghaddieditbecamecleartomethathemusthavebeeningreatpain.Forhimtohavebittenafamilymemberhecouldnothavebeenhimself.MuchthesamefortheotherstorywhenIlearnedthatmyfriend'swifehadjustlefthim. Weareallbeingsofourenvironmentsouropinionsandfeelings.Andallofthosethingscancauseyoutosayanddothingsthatcan'tbeunderstoodbythosewhoarenotinthesamesituationwithyou. Ifyoumeetsomeoneeitherbehavingoutofcharacteroractinginawaythatdoesn'tseemtofitthesituationputoutyourhandandbepatientwhenyouthinkitisleastpossibleforhimtodoso.Youmayturnaroundastorythathasasadendingsimplybyyouractions. 1WhatistheinfluenceoftheincidentmentionedinParagraph1? A.Ithurthisfather'sfeelingdeeply. B.Ithaspuzzledtheauthoreversince. C.Itleftadeepimpressionontheauthor. D.Itmadetheauthordislikedogs. 2Whydidtheauthor'sfriendsayharshwordstotheauthor? A.Hewasill﹣tempered. B.Hewassufferingthepainoflosinghiswife. C.Hewasbotheredbyanunexpectedvisit. D.Theyoncequarreledandhecouldn'tforgivetheauthor. 3What'stheauthor'sadvicetous? A.Helpthoseinneed. B.Lookbeforeyouleap. C.Respectforothersisakindofvirtue. D.Learntoputyourselfinothers'shoes.
Ourmindisapowerfulthingwhichcaneitherimproveorruinourmood.Manyofushaveproblemswithnegativethoughtsplayingonthechannelofourmindsbutifyou'reengaginginitconstantlyandyoubelieveititcouldbedestroyingyoursenseofself﹣esteem.1 Whatcanyoudo?Herearesomesuggestions 1.Liveinthemoment Self﹣talkissosubtlethatweoftendon'tnoticeitseffectonourmoodandbeliefsystems.Keythingstonoticeareifonlyorwhatifstatementstheformerkeepyoustuckinthepastwithregretwhilethelatterkeepyoufearfulofthefuture.2Sostayinthepresentmoment. 2.Visualizethegoodthings Ifwewanttochangethenegativetapesplayinginourheadswehavetovisualizeourselvespositively﹣thatmeansseeingyourselfnon﹣judgmentally.Howwouldthatlook? Drawapictureinyourmindandexpandonit. 3.3 Whateveryoubelieveyou'llexperiencemoreandyou'llalsofindyourselfbehavinginwaysbelievethatareinyourbeliefs.Sostartbelievingthebestaboutyourselfactasifyoubelievethatyou'reavaluableandworthyperson. 4.Developpositivethoughts 4Whatareyourstrengths?Whatareyougoodat?Keepyourthoughtsinthehere﹣and﹣now.InsteadofsayingI'mnotgoodenoughtrysayingIamcapable.IacceptmyselfthewayIam. Thinkingpoorlyaboutourselvesgetsusnowhereandisextremelyself﹣limiting.5 A.Payattentiontothecauses B.Recognizethatactionsalwaysfollowbeliefs C.Thereisnothingyoucandoaboutthepastandthefutureisn'thereyet. D.Inshortitbringsyourfocusonyourfailuresandthatgetsyounowhere. E.Negativethoughtsaccountforbadfeelingsthathookyouintobelievingthatyou'reafailure. F.Insteadofalwaysputtingyourselfdownthinkofsomethingsyouactuallylikeaboutyourself. G.Decidetodaytoturnoffthenegativeself﹣talkchannelinyourmindanddevelopyourtruepotential.
玉米是一种二倍体异花传粉作物可作为研究遗传规律的实验材料.玉米子粒的饱满与凹陷是一对相对性状受一对等位基因控制.回答下列问题. 1在一对等位基因控制的相对性状中杂合子通常表现的性状是. 2现有在自然条件下获得的一些饱满的玉米子粒和一些凹陷的玉米子粒若要用这两种玉米子粒为材料验证分离定律写出两种验证思路及预期结果.①将两种玉米分别自交若遵循基因的分离定律则某些玉米子代会出现31的性状分离比 ②让饱满的玉米子粒和凹陷的玉米子粒杂交如果子一代表现出两种性状且比例为11说明遵循分离定律.
7.5分Peopletendtoacceptgroup'sstandardsofbehaviorandthinkinginagroupwork.Manyillustrations例证couldbegivenofthisfromeverydaylifebutwhatisofparticularinteresttopsychologistsishowmuchpeople'sjudgmentsandopinionscanbechangedasaresultofgrouppressure.Aschandothersnoticedthatpeopleinagroupwillagreetostatementsthatarecontrarytotheevidenceoftheirsenses.Itwouldbeamistaketothinkthatonlyparticularchangeablepeoplearechosentotakepartinexperimentsofthistype.Usuallyhighlyintelligentandindependentpeopleareused. Inatypicalexperimentthisiswhatmayhappen.Theexperimenterasksforvolunteerstojoinagroupwhichisinvestigatingvisualsense.Theparticipantsarenotthereforeawareoftherealpurposeoftheexperiment.Eachvolunteeristakentoaroomwherehefindsagroupofaboutsevenpeoplewhoarecooperatingwiththeexperimenter.Thegroupisshownastandardcardwhichcontainsasingleline.Theyarethenaskedtolookatasecondcard.Thishasthreelinesonit.Oneisobviouslylongerthanthelineonthefirstcardoneisshorterandonethesamelength.Theyhavetosaywhichlineonthesecondcardisthesamelengthasthelineonthestandardcard.Theothermembersofthegroupanswerfirstbuttwhatthevolunteerdoesnotknowisthattheyhavebeentoldtopickoneofthewronglines.Whenhis turncomesheisfacedwiththeconsistentopinionoftherestofthegroup﹣alltheothershavechosenlineAbuthequiteclearlyseeslineBascorrect. Whatwillhedo?AccordingtoAschmorethanhalfofthevictimschosenwillchangetheiropinion.Whatisequallysurprisingisthatwheninterviewedabouttheiranswersmostexplainedthattheyknowthegroupchoicewasincorrectbutthattheyyieldtothepressureofthegroupbecausetheythoughttheymustbesufferingfromanopticalillusion视觉假象orbecausetheywereafraidofbeingdifferent. 1Thepsychologistsareespeciallyinterestedin. A.theevidenceoftheexperiment B.thechangesintheattitudesofpeople C.thedifferenceinpeople'sbehavior D.thedegreeofchangesofpeople'sopinions 2Whymorethanhalfofthevictimschangestheiropinionsintheexperiment? A.Becausetheyhadbeentoldabouttheanswer. B.Becausethoughtthegroupchoicewascorrect. C.Becausetheysubmittedtothegrouppressure. D.Becausetheireyesweresufferingfromillusion. 3Thepurposeoftheauthorinwritingthispassageisto. A.illustratetheinfluenceofgrouppressureonindividuals B.encouragepeopletoactagainstanygroup'sopinion C.invitemorevolunteerstojoininAsch'sexperiment D.tellthereadershowtoperformpsychologicalexperiment
StartingthisSeptemberfreshmenatTsinghuaUniversitywillhavetotakeswimmingcourses.Theywon'treceivetheirdegreesuntiltheypassthetest1success.Exceptionswillbeallowedforstudentswithcertainphysicalormentalconditionsif2provebymedicalstaff. Actuallyviewingtheability3swimasamustforstudentsisnotsomethingnewtothisuniversity.Itwasa4requireintheearly20thcentury.Laterit5dropduetoarisingnumberofstudentsandalackoffacilities设施. Asfor6newruleopinionsvarygreatly.Somestudentswelcomeitsayingit'sanecessaryskill7cansaveliveswhileothersarguethatit'snotreasonabletolinkdegrees8swimmingability. InresponsetothenegativereviewsLiuBoheadoftheDivisionofSportsSciencegavethefollowingexplanation.9awatersportswimmingdoeslessharmtojoints关节andmusclesandishelpfulinimprovingstudents'endurance.10consequenceit'sbeneficialtostudentsinthelongrun.
Cassielivedalonelylife.Shewouldwanderthroughtheforesteating1fallfruitswhileotherbirdsflewamongthetrees. Whycannotyoufly?theywouldask.Yourweaklittle2wingcannotevenliftyouofftheground!theywouldteaseher.You're3shametobirdstheywouldoffendher. Cassiewasfeelingincreasinglyfrustratedand4usesoshemadeuphermindtoleavetheforestforgood.Justasshewalkedfreefromtreessheheardadeepvoice5callfrombehind.Cassieturnedaround.6wasalargetreethatsignaledtohertocomebackintotheforestWeneedyoubadlyheresaidthetree.Werelyonyou7eatourfruitsandspreadourseeds.Theotherbirdsmaythinkyouareworthlessbutyouareactually8muchusefulbirdintheforest.Pleasedon'tgoyouareirreplaceable.Cassicbeamedforthefirsttimeinmanyweeksand9returntotheforest.Thefruitshadnevertastedsogood. It'seasytocompareyourskillstotheabilitiesofothersandfeelinadequate.It'seasytolistentothenegativevoicesofothersandbelievethem.Butbear10mindthatyouareessentialyouareremarkableandyouareirreplaceable!
Noteveryonedealswiththeirfeelingsasanopenbookforotherstoread.1Learntoopenupinordertoimproveyourmentalhealth. 2Acceptthisandmoveon.Giveyourselfsometimetohavesweatypalmsorashakyvoicesinceitwillgetbetterwithpractice. Askpeopleopen﹣endedquestions.Tobeginpracticingopeningupyouneedtoengageinhonestopenconversation.TryaquestionlikeHowarethingsgoingatwork?insteadofHow'sitgoing?togetanopenanswer.Theninturnansweropen﹣endedquestionswithhonestanswersinsteadofFineorOK.3Howeverinmostcasespeopleareflatteredthatyouarelisteningtothemandinterestedintheirlife. Tryemulating效仿someonewhoisveryopen.Observetheminasocialsituation.Thentrytoactasifyouarethemoccasionally.Manyopenbehaviorsarelearnedandnotanaturalpartofpersonality.4 Avoidbeingaknowitall.Somepeoplethinkadviceisopeningupbutitisunlikelytohelpyoumoreopen.Whenyouwanttogiveadvicelistenandtrytolearnsomethingnewfromthesituation. 5Scheduleatleastonelongconversationperweek.Intheconversationyoutellsomeoneabouttheemotionalanddifficultpartofyourlife.Getintothepracticeofopeningupaboutwhat'sgoodandbadinyourlife. A.Inthiscasepracticecanmakeperfect. B.Callclosefriendsandfamilymembersmoreoften. C.Askingpeoplepersonalquestionsisnotalwaysproper. D.Tryconnectingabouthobbiesinterestsvacationsorbooks. E.Listeningpatientlyisagreatwaytoovercomefearofsharingemotionsinpublic. F.Understandthatthereisusuallysomefearwithopeninguptootherpeople. G.Howeverclosingyourselffromnewpeoplecanstopyourpersonalgrowth.
7.5分Itseemsthatelectronicdevicesjustkeepgettingsmaller.ScientistsintheUnitedStateshaveannouncedthecreationofthefirsttransistorwithonlytwodimensions二维. Atransistorisasmallelectronicdevicethattransfersorcarrieselectroniccurrent.Scientistshopethesenew2Dtransistorswillbeusedforbuildinghigh﹣resolution高分辨率displaysthatneedverylittleenergy. Twogroupsofscientistscreatedthese2Dtransistors.Theyreportthatthetransistorsareonlyafewatomsthick. Usuallytransistorsaremadewiththeelementsilicon硅.ComputerprocessorsmemorychipsTVscreensandotherelectronicdevicescontainbillionsofsilicon﹣basedtransistors.Buttheseverysmallelectricalpartshavecertainlimitations. DimitrisIoannouisanelectricalengineeringprofessoratGeorgeMasonUniversity.Hesaysthetraditionaltransistorhasbeenimprovedasmuchasitcanbe.Headdsthatresearchershavebeenlookingfornewmaterialswithspecialfeaturesandtheywanttransistorstobeseenthroughandsoft. Ifthelayersareverythinthetransistorcanbecomeflexiblesoitdoesn'thavetoberigid坚硬的likeitwouldbeinasiliconchip.SopeoplecanthinkofapplicationslikewearableelectronicstelevisionscreensandotherthingssaidIoannou. Thesenewtransistorscanalsocarryhighercurrent.Theyalsocanmovethecurrentmuchfasterthantraditionaltransistors.Thisisimportantforhigh﹣definitionscreens. DimitrisIoannousaysthescientificsuccesscouldproveveryusefulinthefuture.Nowhowgoodandhowusefulitwillbeit'sstillinthestageofresearchbutitcertainlyisanadvancesaidIoannou. 1WhichofthefollowingstatementsaboutthenewlycreatedtransistorisTRUE? A.Theyareexpectedtobeusedinhigh﹣resolutiondisplays. B.Thetransistorsaremadewiththeelementsilicon. C.Theyarerigidjustliketraditionaltransistors. D.Theyhavealreadybeenputintoactualuse. 2WhatdoestheunderlinedsentenceinParagraph5mean? A.Thetraditionaltransistorshavebeenchangedintotwo﹣dimensionalones. B.Manyofthetraditionaltransistorshavebeenimprovedovertheyears. C.Thetraditionaltransistorhasbeendevelopedtoitsfullest. D.Thetraditionaltransistorhasbeendevelopedquitewell. 3WhatisDimitrisIoannou'sattitudetowardsthecreationofthenewtransistors? A.Negative. B.Neutral. C.Indifferent. D.Positive.
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