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如图,在Rt△ABC中,∠A=90°,AB=6,AC=8,点D为边BC的中点,点M为边AB上的一动点,点N为边AC上的一动点,且∠MDN=90°,则sin∠DMN为( )
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如图Rt△ABC中∠C.=90°AC=8BC=4PQ=AB点P.与点Q.分别在AC和AC的垂线AD上
在Rt△ABC中∠C.=90°AC=6BC=8点D.E.分别是ACAB边的中点那么△CDE的周长为.
如图Rt△ABC中∠ACB=90°AC=BC=2若把Rt△ABC绕边AB所在直线旋转一周则所得几何体
在Rt△ABC中∠C.=90°AC=6AB=10则BC的值为
6
8
10
如图在Rt△ABC和Rt△DCB中AB=DC∠A=∠D=90°AC与BD交于点O则有△_______
如图在Rt△ABC中∠C.=90°D.是AC边上一点DE⊥AB于点E.若DE=2BC=3AC=6求A
如图在Rt△ABC中∠ACB=90°CD是AB边上的中线DE⊥AB于点D.交AC于点E.求证∠AED
如图Rt△ABC中∠C=90°AC=8BC=4PQ=AB点P与点Q分别在AC和AC的垂线AD上移动则
如图在Rt△ABC中∠A=90°BD平分∠ABC交AC于点D且AB=4BD=5那么点D到BC的距离是
如图Rt△ABC中∠C=90°AD平分∠CABDE⊥AB于E.若AC=6BC=8CD=3.1求DE的
如图在Rt△ABC中∠ACB=90°AC=8BC=6CD⊥AB垂足为D则tan∠BCD的值是.
如图Rt△ABC中∠C.=90°现将直角边AC折叠到AB边上点C.落在AB边上的E.点折痕为AD.若
如图在Rt△ABC中∠C.=90°AC=6BC=8.把△ABC绕AB边上的点D.顺时针旋转90°得到
如图在Rt△ABC中∠ACB=90°CD是AB边上的高AC=6AB=9则AD=
2
3
4
5
如图所示在Rt△ABC中AB=8AC=6∠CAB=90°AD⊥BC那么AD的长为
1
2
3
4.8
如图在Rt△ABC中∠C.=90°D.为AB的中点DE⊥AC于点E.∠A.=30°AB=8则DE的长
如图1168在Rt△ABC中∠ACB=90°CD⊥ABAC=6AD=3.6则BC=_______
如图在Rt△ABC中∠ABC=90°AB=12cmBC=5cmAC=13cm若BD是AC边上的高则B
如图在Rt△ABC中∠C.=90°AC=6BC=8把△ABC绕AB边上的点D.顺时针旋转90°后得到
如图Rt△ABC中∠C.=90°AD平分∠CABDE⊥AB于E.若AC=6BC=8CD=3.1求DE
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withsomuchtroublewefailedtocompletethetaskontime. A.Faced B.Face C.Facing D.Toface
某科研小组的工作人员通过用不同浓度的秋水仙素对大蒜二倍体鳞茎生长点进行不同时间得处理研究了不同处理对大蒜根尖细胞染色体加倍率的影响某一分裂组织或细胞群中染色体数目加倍细胞的百分数其实验结果如图据图判断下列叙述中正确的是
蛙受精卵下部含有一些特殊的蛋白质和mRNA称为生殖质.用紫外线照射受精卵下部能够破坏生殖质.某研究小组选择受精卵进行探究实验处理方式和实验结果如下 有关分析不正确的是
Youcan'timaginewhatgreateffortswehave. A.taken B.provided C.used D.made
Mother'sDaycandatebacktotheancientGreekswhoheldfestivities庆典inhonorofRheathemotherofthegods.AndtheearlyChristianscelebratedMother'sDayonthefourthSundayofLent大斋期inhonorofMarythemotherofChrist.HowevertheMother'sDaywascancelledbecauseoflackoftime.In1872JuliaWardHoweorganizedadayformotherswhowereworkinghardforthecauseofpeace.ItisgreatlandmarkinthehistoryofMother'sDay. In1907AnnaM.JarvisateacherfromPhiladelphiastartedamovementtosetupanationalMother'sDayinhonorofhermother.ThenacelebrationwasheldforAnna'smother.Annapresentedsomewhitecarnationshermother'sfavoriteflowerstohermotheronthatday.SevenyearslaterAnna'shardworkfinallypaidoffandin1914PresidentWoodrowWilsonannouncedthesecondSundayinMayasanationalholidayformothers. GraduallyMother'sDaybecameverypopularintheUS.ActuallythesecondSundayofMayhasbecomethemostpopulardayoftheyear.EventhoughAnnahasbeendeadforlongMother'sDaylivesonandhasspreadtolotsofcountriesallovertheworld.AlthoughmanycountriesaroundtheworldcelebrateMother'sDayatdifferentdatessomecountriesincludingDenmarkFinlandItalyTurkeyAustraliaandBelgiumstillcelebrateMother'sDayonthesecondSundayofMay. 35.WhodidancientGreeksholdfestivitiesinhonorof? A.MaryB.RheaC.AnnaD.Julia 36.WhydidAnnapresentsomewhitecarnationstohermother? A.Hermotherlikedwhitecarnationsverymuch. B.Shedidn'thaveenoughmoneytobuyotherthings. C.Sheherselflikedwhitecarnations. D.Itwasatraditioninherhometown. 37.Whatisthebesttitleforthepassage? A.Annaandhermother. B.Mother'sDayinancientGreece. C.ThehistoryofMother'sDay. D.People'sopinionsonMother'sDay.
Measuringupto10.5feetinlengththewesterngreenmamba曼巴蛇isthesecondlongestsnakeinAfricawiththeblackmambabeingthefirst.Itisalsothemostagile敏捷的snakeinthemambafamily.Theircolorischangeablewhichhelpsthemjointheirenvironment.Anotherdistinctivefeatureofthesnakeisitslongtailwithasharppoint. Thewesterngreenmambalivesinrainforests.Beinganarborealspeciesthesesnakesspendmostoftheirtimemovingamongthetreetops.Howevertheyusuallyleavetheirtreestopursueapotentialmealontheground.Thewesterngreenmambaismostlyactiveatdaybutcanalsobeseenhuntingatnight. Thedietofawesterngreenmambaconsistsofbirdsandavarietyofsmallmammalssuchassquirrelsmiceandevenbats.Thesesnakeswillapproachtheirtargetswiththehelpoftheirnaturalskincolor.Whentheyarecloseenoughtheywillbitetheirvictimsandinjectthemwithvenom毒液quickly.Oncethetargethasdiedtheweaterngreenmambawillswallowitsmealwhole.Iffacedwithdangerthesesnakeswilltrytorunaway.Iftheyarecorneredhowevertheywillbecomeextremelyaggressiveandstrikewiththeirsharpteethrepeatedly.Thefemaleweaterngreenmambaistheonewholayseggs.Shewilllayeggsanywhere.Theyoungsnakesarecompletelyindependent.Themotherandfatherplaynopartinraisingthebabysnakes.Thebabiesarebornwitheverythingtheyneedtosurviveinthewilderness.Theywillhavealmostnonaturalpredators捕食者toworryaboutwhentheyreachadulthood. 30.Whatdoestheunderlinedwordarborealinthesecondparagraphprobablymean? A.Mainlyfeedigonmeat. B.Mainlyfeedingonplants C.Livingontreesmostofthetime D.Livinginthegrassmostofthetime 31.Whenisthewesterngreenmambamostaggressive? A.whenithastoprotectitseggs B.Whenitissearchingforfood. C.Whenitapproachesitstarget D.Whenitgetsnowaytoescape 32.Whatcanwelearnfromthetext? A.ThewesterngreenmambacanbefoundalloverAfrica. B.ThewesterngreenmambaisthelongestsnakeinAfrica. C.Thewesterngreenmambaoftenswallowsliveanimalwhole. D.Thebabywesterngreenmambadoesn'tneedcare.
1833年Payen和Personz从麦芽的水抽提物中用酒精沉淀得到了一种对热不稳定的物质它可以使淀粉水解为可溶性糖后来知道这种物质就是淀粉酶.淀粉酶有多种类型如α﹣淀粉酶可使淀粉内部随机水解β﹣淀粉酶则使淀粉从末端以两个单糖为单位进行水解.如图为研究pH对两种淀粉酶相对活性影响的研究结果.请据图回答相关的问题 1与α﹣淀粉酶水解淀粉的终产物相比β﹣淀粉酶水解淀粉的主要产物为.从图中可知淀粉酶在人体胃液pH=l.8左右中的活性更高. 2在验证pH对淀粉酶活性影响的实验中酶的相对活力的大小可以用来表示.某同学设计了以下两种实验方案 ①先分别在试管中加底物再加酶然后一起放在相应的pH条件下保温一段时间后检测. ②先分别在试管中加底物再加在相应的pH条件下保温的酶一段时间后检测. 为了使实验结果更加可靠应选择哪种方案并说明理由.
MilestoGotookmeonaroadtripthroughthelifeofagirlthatIthoughtIalreadykneweverythingabout.WitheverysentenceIfeltlikeMileywastalkingtomehavingasister﹣to﹣sisterchat.Shewrotethiswithherheartandthatiswhyitissomeaningful. Mileyisnotacookie﹣cutter千篇一律的celebritylikemanysay.Sheknowswhereshecamefromandwon'tforgetit.Shelivesbyhervaluesandholdsontoherstrongfaith. FamilyisalwaysMiley'stoppriority.IfherlittlesisterNoahwantshertostayhomeandwatchamovieMileywill.EvenifMileygetsinvitedtoacelebritypartyit'sclearthatMileywillchooseherfamilyfirst. MyfavoritepartofthebookiswhenshetalksaboutVanessaa9﹣year﹣oldgirlsufferingfromcysticfibrosis囊性纤维变性.Mileymetheratahospitalandtheybecamefriends.MileykeptincontactwithherfamilyandoftenvisitedVanessaatthehospitalorcalledwhenshewasontour.OnedayMileycalledonlytofindthatVanessa'stimeontheearthhadended.Mileywasverysad.Sheimmediatelygotoffthetourbusandlaydowninafrozenfield.ThiswaswhenMileyrealizedhowimportantitistoloveeverydayandnottakeitforgranted.ThisisjustoneofMiley'smanybeautifullstories. Mileyconnectswithreaders.ForsomeonesoyoungMileyisoneofthemostbrilliantpeoplethatIhaveeverseen.Herfamehasn'tchangedhershestaysgroundedwiththehelpofherfamilyandherfaith. WhenthisbookcameoutIbecameMiley'snumber﹣onefanalloveragain.InreadingMilestoGoIfeltlikeapartofthefamily. 25.WhydoestheauthorthinkMilestoGoisverymeaningful? A.Mileywrotethebookwithallheremotions. B.Onecanhaveaheart﹣to﹣hearttalkwithitsauthor. C.IttellsmanyinterestingstoriesaboutMiley'sfamilylife. D.Ittellsaninspiringstoryofagirlbravelyfightingagainstherillness. 26.Wecanlearnfromthetextthat.Miley. A.lovesherfamilyverymuch B.regardsherworkastoppriority C.likeswatchingTVverymuch D.wasonly9yearsoldwhenshewrotethebook 27.WhichofthefollowingwordscanbestdescribeMiley? A.Ambitiousactiveandbrave. B.Cautioussensitiveandpatient. C.Lovelyhumorousandeasy﹣going. D.Considerateindependentandstrong﹣minded. 28.Inwhichcolumnofanewspapercanwemostprobablyfindthistext? A.Culture. B.Entertainment. C.BookReview. D.TravelGuide.
分离出某动物细胞的三种细胞器经测定它们有机物的含量如图所示.下列有关说法正确的是
WhenIwasnineyearsoldIlovedtogofishingwithmydad.Buttheonlythingthatwasn'tveryfunaboutitwasthathecouldcatchmanyfishwhileIcouldn'tcatchanything.Iusuallygotprettyupsetandkeptaskinghimwhy.HealwaysansweredSonifyouwanttocatchafishyouhavetothinklikeafish.IrememberbeingevenmoreupsetthenbecauseI'mnotafish!Ididn'tknowhowtothinklikeafish.BesidesIreasonedhowcouldwhatIthinkinfluencewhatafishdoes? AsIgotalittleolderIbegantounderstandwhatmydadreallymeant.SoIreadsomebooksonfish.AndIevenjoinedthelocalfishingclubandstartedattendingthemonthlymeetings.Ilearnedthatafishisacold﹣bloodedanimalandthereforeisverysensitivetowatertemperature.Thatiswhyfishprefershallowwatertodeepwaterbecausetheformeriswarmer.Besideswaterisusuallywarmerindirectsunlightthanintheshade…ThemoreIunderstoodfishthemoreIbecameeffectiveatfindingandcatchingthem. WhenIgrewupandenteredthebusinessworldIrememberhearingmyfirstbosssayWeallneedtothinklikesalespeople.Butitdidn'tcompletelymakesense.MydadneveroncesaidIfyouwanttocatchafishyouneedtothinklikeafisherman.WhathesaidwasYouneedtothinklikeafish.Yearslaterwithgreateffortstopromotelong﹣termservicestopeoplemucholderandricherthanmeIgraduallylearnedwhatweallneedistothinkmorelikecustomers.Itisnotaneasyjob.Iwillshowyouhowinthefollowingchapters. 42.Whatdidthewriter'sfatherreallymean? A.Toreadaboutfish. B.Tolearnfishingbyoneself. C.Tounderstandwhatfishthink. D.Tostudyfishinginmanyways. 43.Accordingtothewriterfisharemostlikelytobefound. A.indeepwateronsunnydays B.indeepwateroncloudydays C.inshallowwaterundersunlight D.inshallowwaterunderwatersidetrees 44.Afterenteringthebusinessworldthewriterfound. A.iteasytothinklikeacustomer B.hisfather'sfishingadviceinspiring C.hisfirstboss'ssalesideasreasonable D.itdifficulttosellservicestopoorpeople 45.Thispassagemostlikelycomesfrom. A.apopularsalesbook B.afishingmagazine C.anovelonchildhood D.atextbookaboutfish.
﹣Whichshirtwouldyouliketobuy? ﹣forIcan'tdecidewhichoneisbetter. A.None B.Neither C.Either D.All
AtthistimetomorrowImyfavouriteNBAgames. A.enjoy B.willbeenjoying C.amenjoying D.haveenjoyed
﹣Whatmadehersounhappy? ﹣withherclosefriend. A.Toargue B.Argued C.Arguing D.Argue
5waystomakeyoufullofvigor Herearesometipstofollowatnightthatwillhelpboost提高yourenergyinthemorning. Logout退出yourinstantmessengerFacebookandemail.Inthemiddleofthenighttheycaninterruptyoursleep.36Andmorethanlikelyifyourfriendsseethatyou'reloggedoutthey'lllogouttoo. Turnoffyoucellphonewhenit'stimeforbedbutdon'tjustsetitonvibration震动.37Thusabuzz震动声canbejustasloudasrings.Besidesifyourfriendshavenoonetotalktomaybethey'llbeinspiredtoturnofftheircellohonesandgotosleeptoo. Getinthehabitofshuttingdownyourcomputer﹣﹣﹣especiallyifit'sinyourbedroom.SometimesjustloggingoutyourinstantmessengerorFacebookisnotenough.38Getyourcellphoneoutofyourroomcompletely.39Whileyourcellphonebatteryisrestoringyoucangetthesleepthatyouneedtorechargeyouownbattery.Havingyourcellphoneinanotherroomcanreducethechancethatyou'lluseitduringbedtime. Makegettingenoughsleepyourwaytolookandfeelgood.Gettingenoughsleepisagreatwaytolookandfeelrefreshedinthemorning.Togetthesleepthatyouneedyou'dbettertellyourfriendsthatyouwillreceiveyourlasttextemailorphonecallanhourbeforebedroom.40 A.Brightlightfromthescreencanmakeithardtofallandstayasleep.. B.Theycanbotheryouevenifyoudon'tgetuptoanswerthem. C.Thiswaythey'llknowtheircallsortextswillhavetowait. D.Lateatnighteverythingelseisquiet E.Usingcellphonetoomuchisbadforyourhealth. F.It'snousehavingyourcomputeronatnight. G.Trychargingyourcellphoneovernightinaseparateroom. 36. 37. 38. 39. 40.
为探究除草剂24﹣D对水稻田间鸭跖草防治的合适浓度进行相关实验实验结果如表所示除草剂的作用主要使植株平均株高下降下列对实验的有关叙述错误的是
Weallwanttogivegiftsthatareappreciated.Thattakestimeandtalent.Hereareafewstepsthatwillhelpyouchoose. Preparetobuygiftsinadvance Choosingperfectgiftsforyourfriendsandfamilystartsbeforeyoureachastore.Youwillbuythebestgiftsforeachpersonbydoingyourhomeworkinadvance. Watchwithyoureyes IfyouarearoundthepersonoftenwatchwhathepicksupinstoreandwatchesonTVorwatchwhathelooksatinnewspapers.Thosecluescanbetranslatedintogiftsatanothertime. Tuneinyourfriendswithyourears Adirectgiftmethodistoaskthepersonwhathewants.Thenlistentowhatissaid. Asksomeoneelseaboutgifts Asksomeoneclosetotherecipient接受者forafewgiftsuggestions.Maybetheywillevengowithyoutobuythegift.Betteryetmaybetheywillbuythegiftforyou! Makealistofpotentialgifts Beforeyoueverleavehomemakealistofpotentialgiftsforthisperson.Infactcheckforgiftideasonlinefirst.Maybewithalittleluckonlineyouwon'tevenhavetoleavehome. Whenyougivesomeoneagiftitismorethanapresent.Whatyougivehimshowsyourfeelingforhimoryourthoughtsofhim.Whenyougivesomeoneagiftthatletshimknowhowyoufeelabouthimyouaregivingagifttherecipientwilltreasureregardlessofthepriceofit. Ifyouhavesuggestionsaboutchoosingtheperfectgiftpleaseletusknowhere.Thankyou. 60.Thepassagemainlytellsthereader. A.whatchoosinggiftscosts B.howtochooseperfectgifts C.whatgiftsyoumaygivesomeone D.howusefulgiftsaretoyourfriend 61.WhenyoubuyagiftforyourfriendyoushouldNOT. A.askhimwhathewantsandfollowhiswords B.preparetobuythegiftinadvance C.choosethegiftonyourown D.asksomeoneclosetotherecipientforadvice 62.ThetitleWatchwithyoureyessuggests. A.stayingwiththerecipientasoftenaspossible B.alwaysdoingshoppingwiththerecipient C.watchingTVorreadingnewspaperswiththerecipient D.watchingtherecipient'slikesordislikes 63.Fromthegiftyougivetheperson. A.hecanknowhowyoufeelabouthim B.youcanreceivemoregiftsthanwhatyougivehim C.hecandecideifit'sworthtreasuringbytheprice D.hecanrealizeyourfeelingforthegift.
下面一篇短文中共有10处语言错误每句最多有两处错误每处错误只涉及一个单词的增加删除或修改. 增加在缺词处加一个漏字符号∧并在其下面写出该加的词. 删除把多余的词作斜线\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词. 注意1每处错误及其修改仅限一词 2只允许修改10处多者从第11处起不计分. Ifyouareastudentorunder20youcantakeparttheDestinationEuropetravelcompetitionbutwintheholidayofalifetime.YouwillspendtwomonthstouringEuropeandvisitthecountriesofyourchoice.What'sworseyoucangowithmybestfriend!AllyouhadtodoaretoanswerourEuropeanculturequiz.PleasewriteaboutaplaceinEuropewhereyouwouldparticularliketovisit.Thefirstthreewithcorrectanswerswillwinatwo﹣monthsholidayaroundEuropefortwo.
在哺乳动物体细胞核中除一条X染色体外其余的X染色体高度螺旋化失活成为巴氏小体如图所示.失活现象发生在胚胎发育的早期并且在体细胞中这种失活是不可逆的.巴氏小体的数目及形态可通过显微镜观察通常位于间期核膜边缘.请回答 1利用显微镜观察巴氏小体可用染色. 2体育运动会上采用巴氏小体方法进行性别鉴定理由. 3色盲是一种常见的单基因遗传病单基因遗传病是指受控制的遗传病.一对色觉正常的夫妇生了一个色盲女儿请分析其原因该女儿与色觉正常的男性婚配生一个色觉正常儿子的几率为.
DrSmithtogetherwithhiswifeanddaughtersvisitBeijingthissummer. A.isgoingto B.aregoingto C.wasgoingto D.weregoingto
如图1为某种绿色植物叶片的气孔结构示意图中间两个呈肾形的细胞称为保卫细胞它可调节气孔的开闭.研究人员将该叶片放在内部温度为15℃的密闭容器中研究光照强度与光合速率的关系结果如图2所示.请回答 1保卫细胞中存在有叶绿体在光照条件下其合成ATP的场所有. 2从图1中可以看出两个细胞贴近部分的细胞壁较厚伸缩性较小外侧部分较薄.保卫细胞的叶绿体在适宜光照下进行光合作用利用CO2使细胞内pH值增高淀粉磷酸化酶水解淀粉为磷酸葡萄糖细胞内渗透压上升或下降保卫细胞吸水或失水这时气孔导度增大或减小.光照强度过强时叶片温度会升高蒸腾作用会加强保卫细胞水分的运动方向如图1所示植物关闭气孔可以增大或减小水分的散失. 3据图2分析在1klx的光照条件下该叶片在5小时内由光合作用产生的O2量约为mL.
Ihadreachedtheairportabout30minutesago.Itwasavery36threedaysformewithlotsofmeetings.SoIwasgladtohavethe37timetomakemynotesonwhatI38todothefollowingday.Butthencamethe39thatmyflighthadtobe40becausetherewasaproblemwiththeplane. WhenIsatwaitingformy41tobecalledIthoughtaboutmylastmeetingoftheday.Itwasnotabusinessmeetingbutratheraveryenjoyable42withanoldbusinessfriendIhadnotseenforover12years.Ourlunchwasspentrecallingthegoodtimes43experiencingwhathadhappenedinourlivesoverthelast12years.Webothlaughedandsmiledaswerecalledthegoodtimesandthegreatexperienceswehad44together.Attheendofourtimetogetherwebothsaidhowmuchwehad45itandthatwemustdoitagain. Itwasgreattohavethisadditional另外的timetoreplayinmy46allthatwehadtalkedabout.I47howimportantitwastoregularlyrecallthegoodtimesinourlife.Iwasluckyenoughtohavehadthechancetotakeashort48andsharethegoodthingsthathadhappenedinmylifeover12years. Itwasalittlelikelookingatanoldphotoalbum49inacupboardinyourhouse.Beforeyoureyestherearelotsofwonderful50thattakeyoubacktotimesandplacesandmostimportantlytothosepeoplewhoareinthe51. Myflighthomewasfinally52threehourslater.IsmiledasI53theplaneandrealizedthatIwasnotatall54aboutthedelayintheflightasIhadbeenabletospendtheti 36.A.important B.busy C.quick D.useful 37.A.pleasant B.satisfying C.happy D.extra 38.A.had B.failed C.needed D.asked 39.A.announcement B.radio C.opening D.speech 40.A.waited B.cancelled C.taken D.delayed 41.A.flight B.turn C.name D.order 42.A.agenda B.lunch C.party D.discussion 43.A.asfaras B.aslongas C.aswellas D.asgoodas 44.A.spent B.met C.managed D.shared 45.A.got B.enjoyed C.made D.paid 46.A.thought B.spirit C.flight D.mind 47.A.decided B.enjoyed C.realized D.expected 48.A.way B.cut C.method D.break 49.A.stored B.included C.set D.lain 50.A.celebrations B.memories C.awards D.presents 51.A.cupboard B.books C.childhood D.photos 52.A.shouted B.phoned C.called D.sent 53.A.left B.boarded C.jumped D.reached 54.A.upset B.happy C.crazy D.surprised 55.A.passing B.killing C.recalling D.picking
EmilyMycolleaguessayIshouldgethealthinsurance.61doyouthinkofthissuggestionPaul? PaulIthinkit'sreallynecessaryEmily.Thoughyouhavetospendsomemoneyitsavesmoneyinthelongterm.62wemayfallillattimes.Iwillgiveyoumyinsuranceagent'sbusinesscardifyouwant. EmilyInGermanywehaveanationalprogram63provideallcitizenswithfreehealthinsurance.Buthereyouhavenothing. PaulYesIknow.Manycountrieshavenationalhealthinsurance.Americadoesn't. EmilyWhy?As64asIknowtheUSistherichestand65powerfulcountryintheworldisn'tit? PaulWell66influencebyAmericaculturewethinkprivatecompaniescandothingsbetter67thegovernment.Sowerelyonprivatecompaniesforinsurance. EmilyButisn'tthatexpensive? PaulYou'reright.Thehealthsystem68criticizebymanypeopleovertheyears.Theysayitisnotfairtopoorpeople. EmilyButwhat'syouropinion? PaulPersonallyagoodbodyismorereliablethanhealthindurance.That's69Isetasidesometimeforexerciseeveryday70busyIam. 61. 62. 63. 64. 65. 66. 67. 68. 69. 70.
假定你是李华从小喜爱大熊猫一直通过有关网站关注几年前在美国动物园出生的大熊猫苏琳和她的母亲白云.现在苏琳即将过生日.请根据以下要点给动物园工作人员写一份信 内容1.自我介绍2.祝贺苏琳生日3.感谢工作人员4.索取苏琳的生日照片. 要求1.只能用5个句子表达全部内容 2.要使用多种时态 3.开头语已经为你写好. DearSir/Madam GreetingsfromChina!
下列有关叶绿体和线粒体内部分代谢活动的叙述正确的是
紫杉醇具有独特的抗肿瘤作用.研究人员从红豆杉中发现了一种具有产紫杉醇能力的内生真菌.为探究制备红豆杉内生真菌原生质体不含细胞壁的适宜pH和温度进行了如下实验①培养菌株离心收集菌丝体并用渗透压稳定剂洗涤两次②将获得的菌丝体分别置于不同pH或温度的培养液中并加入适量酶液震荡摇匀后每隔一段时间取样过滤离心用渗透压稳定剂洗涤两次后收集纯化的原生质体.③统计原生质体数量结果如下. 分析回答 1步骤②中加酶液的目的是洗涤时选用渗透压稳定剂的理由是. 2结果表明制备红豆杉内生真菌原生质体的适宜条件是. 3检验原生质体再生能力需要配制再生固体培养基培养基灭菌后需要冷却到℃左右才能用来倒平板. 4实验中将收集到的原生质体浓度为30×106个/mL培养液先稀释104倍再各取0.1mL稀释液分别均匀涂布在3个再生固体培养基上培养.一段时间后统计得到的菌落数分别为272124.则原生质体再生率能再生的原生质体数占全部原生质体的比例约为.
有一种XY型性别决定的虫媒花植物其花瓣性状由A﹣a和B﹣b两对独立遗传的基因控制其中B表达为红__为黄色Bb基因同时存在为红色有色花植株中雄性只有红色和黄色没有A基因仅有a基因时雌性植株没有花瓣而不能被昆虫辨识. 1B基因位染色体上在自然种群中控制花瓣性状的基因型共有种. 2某一橙红花植株与分别与红花植株实验一和黄花植株实验二杂交分别得F1. ①对该植株如何操作才能分别完成与红花植株实验一和黄花植株实验二杂交 ②在实验一的F1中雌性红花雌性橙花雌性无花瓣雄性红花雄性黄花=33244则在自然条件下F2中橙花占. ③在实验二中其F1代没有无花瓣植株的产生则黄花植株实验二的基因型为. 3这种植物花色与昆虫之间的关系体现了生态系统的功能.
三孢布拉霉菌能用来生产胡萝卜素但该菌株的高产性状容易退化需要定期筛选出高产菌株研究表明菌体细胞内含有可将无色的TTC还原为红色复合物的物质且菌体细胞内该物质的含量越高还原能力越强胡萝卜素合成能力也越强.结合下列筛选菌株及提取胡萝卜素的流程图回答问题 三孢布拉霉菌→梯度稀释→涂布到含TTC的培养基上→挑取单菌落→扩大培养→收集菌丝并处理→萃取→鉴定 1胡萝卜素的提取方法有从植物中提取等等.上述流程图中提取到胡萝卜素后鉴定一般要用法.胡萝卜素能够治疗夜盲症干皮症等是因为夜盲症干皮症等疾病是由于缺少维生素A而引起的而1分子的β﹣胡萝卜素可被氧化分解成2分子.根据胡萝卜素的理化性质分析为了让胡萝卜素更容易被人体吸收炒胡萝卜时要多加些. 2流程图中将菌液涂布到含TTC的培养基上目的是筛选出合成胡萝卜素较强的菌体高产菌株含TTC的培养基属于填“选择”或“鉴别”培养基.对照组需涂布等量的以判断培养基是否被污染.挑取单菌落时若菌落周围则菌株合成胡萝卜素的能力较强. 3为了验证萃取物是否是胡萝卜素该同学将叶绿素b叶绿素a叶黄素萃取物和色素混合液含叶绿素b叶绿素a叶黄素和胡萝卜素依次点样在滤纸的12345位置如图甲所示并进行分离滤纸条上各色素带的位置为填字母时即可说明该萃取物最可能是胡萝卜素.
假如你班将举行一次英语班会主题为Howtobehealthy请你根据下面提示用英语写一篇发言稿. 注意1.字数120左右开头已给出不计入总词汇可适当发挥. 2.生词零食non﹣staplefood卫生hygiene Dearfriends.
It'sasituationyouneverwanttofindyourselfin.Youareonvacationpeacefullyenjoyingtheplanet'snaturalwonders.Then﹣﹣﹣outofnowhere﹣﹣﹣awildcreatureattacks.Inordertohelpyouwe'vecomeupwithalistoftipsforsurvivingvariousanimalencounters. Bears Bearsbehaveaggressivelywhentheyaresurprised.Yourguideswilltellyoutowearabellinordertoscareawayanybearsthatmaybenearby.Donotgonearbearcubsastheirmotherswillattackviolentlyinordertoprotectthem.Playdeadifthebearattacks. Snakes Snakeskilltheirprey猎物byslowlysqueezinguntilitcannolongerbreathe.Shouldyoufindyourselfbeingtakeninbyasnakeyouareadvisedtoremainstillasstrugglingwillpromptthesnaketosqueeze.Useonearmasprotectionforyourribsanduseyourotherarmtounwindthesnake. Sharks Avoidlyingonthewater'ssurfaceinanareaknowntobepopulatedwithsharks.Yourfiguremaylooklikeasealoranotheranimalthatiscommonpreyforsharks.Theycanfeelvibrations振动fromhundredsofmetersawaysoswimmingislikelytodrawsharkstowardsyou.Makeslowmovementsandtrytogettoshore.Fightbackifyouareattackedbyashark.Targetitseyes. Wilddogs Occasionallywilddogscanbemoreofathreatthanmostpeoplethink.Aswithbigcatsfrighteningthedogwithloudsoundsandmakingyouappearlargercanpreventapossibleattack.Ifanattackdoesoccurremainstandingandtrykickingthedogintheface. 68.Whichofthefollowingisthebesttitleofthetext? A.Dosanddon'tswhenyouareindanger. B.Sometipsforsurvivinganimalencounters. C.Howtopreventananimalattack. D.Howtohaveagoodvacation. 69.Thetextiswrittenfor. A.touristsB.swimmers.C.guidesD.drivers 70.Theunderlinedwordcubsinparagraph2refersto. A.adultbearsB.malebearsC.babybearsD.motherbears 71.Ifyouareattackedbyasharkyoushould. A.playdeadbylyingstillB.hititseyes C.kickitsnoseD.yellforhelp.
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