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七年级（1）班与（2）班各选出20名学生进行英文打字比赛，通过对参赛学生每分钟输入的单词个数进行统计，两班成绩的平均数相同，（1）班成绩的方差为17.5，（2）班成绩的方差为15，由此可知（ ） ...
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在阳光体育活动中某校七年级12两个班共有100人在两个多月的长跑活动之后学校对这两个班的体能进行了测
某校七年级共320名学生参加数学测试随机抽取50名学生的成绩进行统计其中15名学生的成绩达到优秀.估
50人
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为了了解某市七年级学生的体重情况相关人员抽查了该市1000名七年级学生则下列说法中错误的是
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每个七年级学生的体重是个体
抽查的1000名学生的体重是总体的一个样本
这次调查样本的容量是1000
在手工制作课上老师组织七年级2班的学生用硬纸制作圆柱形茶叶筒．七年级2班共有学生44人其中男生人数比
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七年级1班2班共有100名学生其中参加兴趣小组的有29名学生已知1班有的学生参加2班有的学生参加则
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49名．51名
50名．50名
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6分AncientEgyptwasoneofthegreatestcivilizations文明inthehistoryoftheworld.Itlastedforover3000yearsfrom3150BCto30BC. LookingniceandbeingcleanwasveryimportanttotheEgyptians.Mostmenandwomenworejewelry珠宝ofsometype.Therichworejewelrymadeofgoldandsilverwhilethepoorerpeopleusedcopper.Becauseitwassohotmostpeopleworewhiteclothes.Menworekilts男士短裙andwomenworeastraightdress. AncientEgyptwasacomplexsocietyneedingpeopletodomanydifferenttasksandjobs.Mostofthepeoplewerefarmers.TheygrewtheircropsnearthebanksoftheNileRiverwheretherichblacksoilwasgoodforcrops.Thereweredifferentkindsofcraftsmenjobs.Howskilledacraftsmanwaswoulddeterminehissuccess.Mostofthesoldierswerefootmen.Inpeacetimesoldierswouldhelpwithgovernmentprojectssuchasmovingstonesforapyramid金字塔.ScribeswereimportantpeopleinAncientEgyptastheyweretheonlypeoplewhoknowhowtoreadandwrite.ScribescamefromwealthyfamiliesandtookyearsoftrainingtolearntheEgyptianhieroglyphics象形文字. 1.Paragraph2mainlytellsus. A.wheretheancientEgyptianslived B.whattheancientEgyptianswore C.whattheancientEgyptiansate D.whatkindsofjobstheancientEgyptianshad 2.InancientEgyptmostpeopleworewhiteclothesbecause. A.thewhiteclotheslookedclean B.theywereorderedtowearlikethat C.theyweretoopoortobuycolorfulclothes D.theweatherwasveryhotthen 3.Thepeoplewhogrewbarleytomakebeerwheatforbreadandvegetableswere. A.farmers B.craftsmen C.soldiers D.scribes
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根据短文内容选择适当的填空使意思完整每选项至多使用一次.请将答案序号写在短文后横线上. MichaelLeungafamousTVhostinHongKongwrotealettertohisson.Itisnotonly1tochildrenbutalsogoodforallages.Thefollowingarechosen2hisletter. 1.Lifeisshort.Whileyouare3ittodayyou'llrealizeyouareattheendofittomorrow.Sotheearlieryoustarttovalueyourlifethe4youcanenjoyit. 2.Youmightnotbesuccessful5youdon'tstudyhardalthoughalotofsuccessfulpeoplehaven't6highereducation. 3.Idon'texpectyoutosupportmefortherestof7lifesoI'mnotgoingtodothesameforyou.Youwillbelivingonyourownwhenyougrowup. 4.Youcanrequireyourselftobenicetoothers8youshouldn'texpectthesamefromothers. 5.I'vebeenbuyingthelottery彩票foralmosttwenty9butI'mstillpoor.Ihavenevergotthe10placeevenonce.Soyouhavetobesuccessful.Thereisnofreelunchintheworld. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10.
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.
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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．
Nowadaysmanyanimalsarefacingdanger.Suchsituationwon'tbechangedhumansstophuntingthem.A.though B.when C.unless D.because
AccordingtothestudiesfromtheUNtheincreaseofCO2intheairisresponsiblefor85%ofthetemperatureincrease.CO2goesintotheairwhenweburnfossilfuelstorunourindustriescarsandsoon.LuckilyhalfoftheCO2thatweproducedistakeninbyplantstreeslandandtheoceans.Therestgasesarestilllargetocauseworry.Atthesametimewearecuttingdownforeststhattakeincarbonfromtheair. Tosolvetheproblemisnotaneasyjob.DevelopednationssuchastheUSAGermanyandAustraliawillhavetopromisetocutdowngreenhousegasesbyasmuchas25﹣40%.CountriessuchasIndiaandChinathathavealargepopulationandgrowingindustryhavetoleaveasmallergreenhousegasfootprint.Everybodymustbeactiveandsticktoit. 1.HalfoftheCO2thatweproducedcanbetakeninby. A.plantsandtrees B.land C.theoceans D.ABandC 2.Whydoesthetemperatureincrease? A.Peopleuseupusefulgases. B.MoreandmoreCO2goesintotheairbecauseofpeople'sactivities. C.ForestscannottakeinCO2anymore. D.Everybodyhopeswintercanbewarm. 3.Howmanycountriesarementionedinthispassage? A.2 B.3 C.5 D.6
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．
根据对话内容将方框内符合对话情境的句子抄写在答题纸上使对话恢复完整.选项中有两项是多余的. A:HelloCathy.Areyougoinghome? B:Yesbutfirst1Ineedtobuyagift. A:Forwhom? B:Formymother.2 A:OhIsee.Whatareyougettingforyourmother? B:I'mnotsure.3 A:Ofcourse.Letmethink…4 B:Shelikesreadingandtraveling. A:5 B:Igetabookforhereveryyear.Iwantsomethingdifferentthisyear. A:Whataboutabeautifulscarf? B:Goodidea!Thanks. A:You'rewelcome. 1. 2. 3. 4. 5.
感谢你提醒我关于明天的志愿者活动. Thankyoufor.
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．
One'sattitudeisalwaysimportant.Ifyouarelazyandweakyouwillnevertastesuccess.Butifyouare1successandhappinesswillbemorelikelytocometoyou. Iloveeatingpersimmons柿子.Butyoucan'tgetthemuntilautumn.Ifyoutrythembeforetherighttimetheyprobably2bad.InGradeSixbecauseofmypoorgradesmyparentswere3thatIwouldn'tbeabletogetintoanexcellentmiddleschool.They4metostudyharderbutIdidn'treallyunderstandwhytheyweresoanxious焦虑的. SummercameandIstudiedhard.ThehotweathermademesleepyandIcouldn'tconcentrate集中精力onmytextbook.ButeverytimewhenIwantedtostop5mydadwouldsayThinkaboutyour6.Ifyoudon'tworkhardyouwillregret.Ihadtositbackdownagainandreturntomytextbooks.ButallI7wasplayingwithmyfriends. Mydadwouldsaytomewithaseriouslookon8faceIfapersimmontreedoesn'tgrowinsummeritcan'tbear结出fruitinautumn!Onlybyworkinghardcanyougetgoodresults.AfewmonthslaterIsucceededin9thekeymiddleschool.Iwassohappy.Mydadwasrightifapersimmontreedoesn'tgrow10summertherewillbenofruitinautumn.IworkedhardandIenjoyedthefruitofmyhardwork! 1.A.busy B.clever C.hard﹣working D.free 2.A.look B.taste C.turn D.smell 3.A.embarrassed B.worried C.excited D.annoyed 4.A.made B.allowed C.pushed D.pulled 5.A.thinking B.working C.playing D.looking 6.A.future B.hobby C.health D.wealth 7.A.talkedabout B.heardabout C.thoughtaboutD.throwabout 8.A.his B.your C.my D.their 9.A.failing B.reaching C.getting D.entering 10.A.before B.during C.after D.until
Thefirefighterscameintimeandquicklythefire.A.putup B.putout C.puton D.putoff
﹣﹣﹣WouldyoupleaseprovideussomeinformationabouttheearthquakeinQinghaiatthebeginningofthisyear?﹣﹣﹣Sure.It'ssaidthatitstartedtheafternoonofJanuary21st.A.for;on B.with;in C.with;on D.for;in
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