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某学校高一、高二、高三年级的学生人数之比为4:3:3,现用分层抽样的方法从该校高中三个年级的学生中抽取容量为50的样本,则从高一年级抽取的学生人数为( )
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高一上学期数学《》真题及答案
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某中学高一至高三年级的学生参加某项社区服务如果高三年级与高一年级高三年级与高二年级参加此项活动的人数
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某学校高一高二高三年级的学生人数之比为334现用分层抽样的方法从该校高中三个年级的学生中抽取容量为5
某学校高一高二高三年级的学生人数之比为现用分层抽样的方法从该校高中三个年级的学生中抽取容量为50的样
某学校高一高二高三年级的学生人数之比为4∶3∶3现用分层抽样的方法从该校高中三个年级的学生中抽取容量
某学校高一高二高三年级的学生人数之比为 3 ∶ 3 ∶ 4 现用分层抽样的方法从该校高中三个年级的学
某学校高一高二高三年级的学生人数之比为 3 ∶ 3 ∶ 4 现用分层抽样的方法从该校高中三个年级的学
某校高一高二高三年级的学生人数之比为443现按年级用分层抽样的方法抽取若干人若抽取的高三年级的学生
某学校高一高二高三年级的学生人数之比为3∶3∶4现用分层抽样的方法从该校高中三个年级的学生中抽取容量
某高中三个年级共有3000名学生现采用分层抽样的方法从高一高二高三年级的全体学生中抽取一个容量为3
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某学校高一高二高三年级的学生人数之比为现用分层抽样的方法从该校高中三个年级的学生中抽取容量为的样本则
某中学高一至高三年级的学生参加某项社区服务如果高三年级与高一年级高三年级与高二年级参加此活动的人数之
40
55
79
89
某学校高一高二高三年级的学生人数之比为 3 : 3 : 4 现用分层抽样的方法从该校高中三个年级的学
某学校高一高二高三年级的学生人数之比为现用分层抽样的方法从该校高中三个年级的学生中抽取容量为50的样
某中学高一至高三年级的学生参加某项社区服务如果高三年级与高一年级高三年级与高二年级参加此活动的人数之
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某学校高一高二高三年级的学生人数之比是334现用分层抽样的方法从该校高中三个年级的学生中抽取容量
某校高一高二高三年级的学生人数之比为10:8:7按分层抽样从中抽取200名学生作为样本若每人被抽到的
某学校高一高二高三年级的学生人数之比为554现按年级采用分层抽样的方法抽取若干人若抽取的高三年级为
2015年·漳浦三中模拟某学校高一高二高三年级的学生人数之比为334现用分层抽样的方法从该校高中三
某学校高一高二高三年级的学生人数之比为3∶3∶4现采用分层抽样的方法从该校高中三个年级的学生中抽取容
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Ourteacherstriedteachingusaboutdeathduringnursingtraining.AsastudentnurseIknewIwouldseedeathinmy1.Ihadnoideaofthe2itwouldhaveonme3. ThefirstpersonIsawdiewasanelderlymanJohnwhohadbeen4forweeks.Hisheartwas5andthehealth﹣careteamwaskeepinghimcomfortableand6hissymptoms.Hehadstoppedspeakingdaysbeforebutwasstillawakeattimesandhis7whenwespoketohimwasbeautiful. WhenIcameontothe8onemorningthenightstaffsaidhehaddeteriorated恶化overnightandhad9lefttoleave.AtrainednurseandIgavehimabedbathshavedhimandchangedhissheets.ForthenextsixhoursI10hishandandtalkedtohim.Thedoctorcameinregularlyandaskedifheneededmorepainreliefbutheseemed11mostofthetime.Heonly12openedhiseyestosmileatme.Earlyintheafternoonthenursecamebackinandwewashedhisfaceand13hishair.Asshewasjustabouttoleavetheroomshestrokedhishairandsaid:OhJohnjust14.Minuteslaterhedid. Ithasbeen20yearssinceJohn'sdeath.Ihaveseen15deathsinmytimenursing.Ihaveseenstaffgofarbeyondthe16oftheirjobsto17thatapatienthasasgoodadeathaspossible.Iremembersomeoftheotherfacesbutnoneisquiteas18asJohn's.Heandtheprofessionalswhowere19himtaughtmethatit20howwetreatthosewhoaredying. 1A.life B.career C.mind D.family 2A.impact B.difference C.reflection D.affection 3A.instead B.regardless C.therefore D.however 4A.insisting B.challenging C.struggling D.recovering 5A.striking B.failing C.beating D.aging 6A.comforting B.decreasing C.disappearing D.relieving 7A.face B.eyes C.smile D.expression 8A.ward B.classroom C.hospital D.department 9A.days B.hours C.minutes D.seconds 10A.held B.reached C.hugged D.touched 11A.silent B.painful C.peaceful D.anxious 12A.frequently B.occasionally C.hardly D.easily 13A.combed B.tied C.washed D.smelt 14A.comeon B.passaway C.letgo D.goaway 15A.priceless B.constant C.considerate D.countless 16A.qualifications B.ability C.expectations D.exception 17A.pretend B.assume C.believe D.ensure 18A.beautiful B.vivid C.pale D.scary 19A.caringfor B.lookingfor C.bringingup D.cheeringup 20A.trains B.works C.influences D.matters
已知函数fx=x2+3x+m. 1当m=﹣4吋解不等式fx≤0 2若m>0fx<0的解集为ba求的最大値.
IthasbeenfourdaysofdoctorsgivingbadnewsthatIcan'tplayBaseballanymoreLyinghereinmyhot1hospitalbed.IwantbadlytoleavethisplaceIaskmymomto2memykeyswithakeychain﹣asoftpieceof3madefrommyfirstbaseballglovethatI4somuch.Eventhoughitonlyweighsdozensofgrams.itcarriestonsof5.ItcarriesgreatmomentslikehomerunsandchampionshipsaswellasmomentswhereI6andlose.Ijustwanttoholdmypreciousthat7mytruepassion.Intertwined缠绕inthefibersoftheleatheraresomanymemoriesthathave8measaperson. Iamtakentoafieldonahotclearsummerday.I9amixofthejudgesspeakingwiththecoachesonthefieldandthe10shoutingfromthegrandstand.Myteammatesshoesareclickingastheywalkacrosstheseats11waitingforthechampionshipgame.Youcanfeelthepressurethatispushingdownonbothteams.Thejudges12tous:PLAYBALL.Atthatmomenttimespaceandpeopleare13. AllofasuddenI14myeyesasmynursewalksin.Almostanhourhaspassed!I15myfingersupanddownonmypreciousjustfeelingthis16ofthegame.Ittakesmeonawildroadtripthroughmy17whichisnowover.Iambacktoarealityofahospitalbedanda18arm.Thingsseemalittle19now.butIwon'tgiveupmy20forbaseball. 1A.soft B.uncomfortable C.hard D.small 2A.offer B.present C.hand D.show 3A.leather B.wood C.plastic D.cloth 4A.clean B.play C.use D.value 5A.chances B.criterion C.impression D.weight 6A.comedown B.setoff C.strikeout D.hangaround 7A.describes B.symbolizes C.builds D.adds 8A.challenged B.questioned C.promised D.transformed 9A.write B.see C.hear D.meet 10A.players B.audience C.parents D.journalists 11A.patiently B.gladly C.anxiously D.silently 12A.yell B.whistle C.react D.claim 13A.quiet B.shaking C.frozen D.common 14A.close B.open C.cover D.widen 15A.move B.raise C.press D.put 16A.honor B.trip Cskill Dreminder 17A.hand B.brain C.key D.coach 18A.broken B.bad C.strong D.pale 19A.strange B.scary C.pitiful D.tough 20A.passion B.Job C.potential D.qualification
假定英语课上老师要求同桌之间交换修改作文请你修改你同桌写的以下作文.文中共有10处语言错误每句中最多有两处.每处错误仅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:把多余的词用斜线\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.每处错误及其修改均仅限一词;2.只允许修改10处多者从第11处起不计分.LastyearZhangPingyupaidvisittoLondon.WorriedaboutthetimeavailableZhangPingyuhadmadealistofthesiteshewantedtosee.ItwastheTowerwhichshevisitedfirst.Fancy!Thissolidstonesquaretowerhadbeenremainedstandingforonethousandyears.Manynewbuildingshadexpandedaroundit.Thereforeitwasstillpartofaroyalpalaceandprisoncombined.TherefollowedStPaul'sCathedralbuiltaftertheterriblefireofLondonin1666.Itlookedsplendidlywhenfirstbuilt.WestminsterAbbeytoowasveryinteresting.ThenjustashecameoutoftheabbeyPingyuheardthefamoussoundoftheclockBigBenringoutthehour.ThenextdayPingyuwasleavingLondontoWindsorCastle.'PerhapsIwillseetheQueen?'shewonderedasshefallasleep.
Thereisnobetterwaytoexperienceaplacethanthroughthelocalcuisine.Withseveralfoodfestivalshappeningacrosstheworldfindplentyofmotivationheretohelpyouyou'reyourbagsandgoonaglobalcookingexploration. MaineLobsterFestivalUS ThefestivalinRocklandMaineisnotedforitsseafood.CelebratedduringthefirstweekendofAugustforfivedaysitoffersfirst﹣classentertainmentfineartcookingcontestsandmore.Itisexpectedthatover20000pounds9072kilogramsoflobsterareconsumedduringthecourseofthefestival. OktoberfestGermany The16﹣daytraditionalbeerfestivalinMunichisthelargestofitskindintheworld.HeldinSeptemberandOctoberthe2013editionsawI.84milliongallonsofbeerserved.AwidevarietyoftraditionalGermandishesincludingroastporksausageandpotatoorbreaddumplingsarealsoavailable.In2019the186theditionwillbeginfromSept.21andlastuntiltact.6.Entryisfree. MentonLemonFestivalFrance Takingplacesince1896thisfestivalisheldinFebruaryandMarchinMentonontheFrenchRiviera.Basedonanewthemeeachyearimpressivesculpturesandfloatsaredeco﹣ratedwith140tonnesoflemonfruits.In2019thefestivalwillheheldfromFeb.16toMarch3onthethemeFantasticWorlds. ChinchillaMelonFestivalAustralia ChinchillainQueenslandisknownasthemeloncapitalofAustraliaandeveryotheryearinFebruaryitsresidentscelebratethegloriousredandjuicystickinessofwatermelonswiththisfour﹣dayfestivalwhichincludesmelonracesmelonskiingagiantmelonfoodfightandofcoursehavingyourfillofmelons.In2019thefestivalwillbeheldfromFeb. 14一17. 1Wheredoseafoodloversprefertogo? A.Munich. B.Menton. C.Chinchilla. D.Rockland. 2WhatisthemostpopularatOktoberfest? A.Bread. B.Potato. C.Pork. D.Beer. 3WhatisspecialaboutChinchillaMelonFestival? A.Itistheoldest. B.Itlaststhelongest. C.It'sheldeverytwoyears. D.IttakeplaceinAustralia'scapital.
InnoparticularorderherearesomesongsontheMusicappofmyphone: OnaSundayAfternoonbyLighterShadeofBrown﹣Astudentofmineintroducedthisrapsongtomeallthewaybackintheearly1990swhenIwasteachingSpanishatalocaluniversity.ThestoryinthesongtakesplacenottoofarfromwhereIliveinLosAngeles.It'sagooddrivingsongnothingcomplicatedordeep. SaySomethingbyAGreatBigWorld﹣Amorerecentsongaboutacouplelosingcontactwitheachother.Thepianopartisverylittleplayingbutbeautiful. AmericanPiebyDonMcLean﹣Anothersongfrommyyouthinthe80sverypopularwithalmosteveryAmericanofmygeneration.Itretellssomeofthekeyeventsofthemiddle20thcenturyasongofhappymemoriesofthepastandwantingtoreturntothosebettertimes. TheWeightbyTheBand﹣Anotheroldsongoriginallymadepublicin1968butoneIdidn'thearuntilIwasinhighschoolmorethan10yearslater.Idon'tunderstandthewordstothesongcompletelybutthefeelingofthesongisverycomfortingtome. UndertheBridgebyRedHotChiliPeppers﹣ThisLosAngelesgroupwroteasongthatIusedtolistentowhenIfirstmovedtoLAmorethan25yearsago.Ididn'tknowanyoneherewhenIfirstarrived.WhenIgotboredIusedtodriveupanddownthemajorstreetsthatcrossthecityfromeasttowestlisteningtothissongaboutthecityofangelbeingaslonelyasIam.Don'tworry!Ihaveplentyoffriendsnow. 1Whatdoestheunderlinedworddeepprobablymean? A.withskill B.withcomfort C.withanormalmeaning D.withasignificantmeaning 2WhendidtheauthorprobablyheartheWeightbyTheBand? A.In1968. B.In1970. C.Inthe1980s. D.Inthe1990s. 3WhentheauthorfirstmovedtoLAthesongheoftenheardwas. A.SaySomething B.AmericanPie C.TheWeight D.UndertheBridge
TheInterContinentalShanghaiWonderlandwhichwasbuiltintothesideofa1formalabandonedquarry采石场about20milessouthwestofShanghaihasbeenconsideredtheworld'sfirstundergroundhote1ortheworld's2lowskyscraper. Thetopfloorofthehotelislocatedatgroundlevelwitharoofcoveredingreenerywhile16floorsofthehotelarelocatedbelowground.Underwaterareanothertwofloors3guestscanobserveschoolsoffishthrougha15﹣metre﹣wideglasswindow.Apartfromthoseunderwater4roomeveryroominthehotelfeaturesabalconywithviewsofaglass﹣enclosedartificialwaterfall5rundownthequarrywalls.Thehotelisalsotakingadvantage6itslocationinsideasteep288﹣feetdeepquarryandisprovidingbungee﹣jumpingandrock﹣climbingattractionstothrill﹣seekingvisitors. Thehoteltook10yearstocompletewithtotalcostover﹩151million.Over5000peopleparticipatedinthe7constructofthehotel.ThechiefengineerontheprojectChenXiaxiangsaidhisteamregistered39patentsand8makehundredsoftechnologicalbreakthroughs.It'sbeenafightagainstgravityhesaid. Thehotel9designwitheco﹣friendlyprinciplesproducesitsownpowerheatingandlightingthrough10useofgeothermal地热的andsolarenergy.Roomsstartfrom4000Chineseyuanaround﹩576onsomeonlinehookingsites.
如图所示半径r=0.06m的半圆形无场区的圆心在坐标原点O处半径R=0.1m磁感应强度大小B=0.075T的圆形有界磁场区的圆心坐标为00.08m平行金属板MN的极板长L=0.3m间距d=0.1m极板间所加电压U=6.4x102V其中N极板收集到的粒子全部中和吸收.一位于O处的粒子源向第一二象限均匀地发射速度为v的带正电粒子经圆形磁场偏转后从第一象限出射的粒子速度方向均沿x轴正方向已知粒子在磁场中的运动半径R0=0.08m若粒子重力不计比荷=108C/kg不计粒子间的相互作用力及电场的边缘效应.sin53°=0.8cos53°=0.6. 1求粒子的发射速度v的大小 2若粒子在O点入射方向与x轴负方向夹角为37°求它打出磁场时的坐标 3N板收集到的粒子占所有发射粒子的比例η.
IntheUnitedStatesexpertsarecallingformajorchangestotheadmissionprocessinhighereducation TheNationalCenterforEducationalStatisticsorNCESreportedthatU.Scollegesanduniversitiesreceivedmorethanmillionapplicationsbetween2013and2014andadmittedmorethan5millionstudents.Buttheproblemisnotinthenumberofstudentsanewreportsays.ThereportiscalledTurningtheTide﹣MakingCaringCommon. Thereportarguesthattheprocessschoolsusetochoosestudentscausesmajorproblems.DavidHawkinsistheExecutiveDirectorforEducationalContentandPolicy.Hesaysthatmostcollegesanduniversitiesrequiremanythingsfromstudentswhentheyapply. Schoolsusuallyrequireanessaydescribingastudentsinterestsorwhytheywanttostudyatthatschool.Theschoolsalsoaskforlettersfromteachersdescribingwhyastudentisagoodcandidate.But.Hawkinssays.schoolsaremostconcernedwithastudent'shighschoolgradesandstandardizedtestresults. TheEducationConservancyisanorganizationthatfightstomakehighereducationequalandavailable.LloydThackeristheExecutiveDirectoroftheEducationConservancysayingthatthecollegeadmissionprocesshaschangedalot. Overthepast30yearscollegeadmissionshavebecomemorecomplex.Hesaysthatrankingsystemsforcollegesanduniversitiesareabigpartoftheproblem. U.S.NewsandWorldReportisamediacompanythatcreatesalistofwhatitcallsAmerica'sBestColleges.Thecompanybasesthelistoninformationcollectedfromcollegesanduniversitiesacrossthecountry.ThisinformationincludesresultsofstandardizedtestsliketheSATfromallofaschoolsstudents.Higheraveragetestresultshelpputschoolshigheronthelist. ThackerclaimsToomanystudentsarelearningtodowhateverittakesinordertogetaheadevenifthatmeanssacrificingtheirownindividualitytheirhealththeirhappinessandbehavior…… Theimpactonstudentsandonparentsisthatcollegeisallaboutwhereyougo.Therankhasnothingtodowiththequalityofeducationthatgoesonatthecollege. TheHarvardreportstatesthatthebestwaytochangetheadmissionprocessisbychangingcollegeapplications. 1Whenchoosingstudentscollegesanduniversitiesattachgreatestimportanceto. A.theirteachersopinion B.theirpersonalinterest C.theiracademicperformance D.theirreasonsforapplication 2Themediacompanyrankstheschoolsonthebasisof. A.peoplesattitudetowardstheschools B.employmentrateofitsgraduates C.theschoolsteachingquality D.informationliketestresults 3WhichofthefollowingdoesLloydThackerprobablyagreewith? A.Collegesaresupposedtoadmitmoreandmorestudents B.Itisnecessarytoapplyforaproperuniversitybyreferringtotherank C.Thereislittlerelationshipbetweencollegesrankandthequalityofeducation D.Thebettertheapplicantsgradesarethemorelikelytheywillbeadmitted 4Whichofthefollowingisthebesttitleofthepassage? A.HigherRankingsMatteraGreatDeal B.CollegesLooktoChangeAdmissionProcess C.CollegesAdmissionProcessMakesaDifference D.TestingResultsDetermineStudentsFate
IfyouhaveeverfoundyourselflookingforyourkeysmisplacingyourcellphoneorwantingtokeeptrackofyourbicycleorcarthentheTrackRadevice装置thatworkswithyoursmartphonecreatedbyaCalifornia﹣basedcompanyisforyou!At﹩29.95eachnotliketheexpensiveGPSsystemsorwithTrackRPackpurchasedealsyoucan'taffordnottohaveone! Install安装thefreeTrackRapponyoursmartphone.Connecttheapptoyourdeviceandthenyouarereadytogo!SimplyattachtheTrackRtowhateveryoudon'twanttolose.Theentireprocesssettingituponlytakes5minutesorless. IfyouhavethehardTrackRyoucanjusthideitunderyourcar'sfloormat.Inthetrunkorsomewhereitwon'tbefoundifyourcargetsstolen.IfyouforgetwhereyouparkedyourcartakeoutyoursmartphoneandopentheTrackRapp.Taponthelostitemicononthescreenandtheappwilltellyouexactlywhereitis. Youcanalsoattachittoyourpet.Putitontheircollarandtheproblemofsearchingforthemastheyrunofftonearbyplaceswillbeover!Attachittoyourkeysandwalletandneverwasteaminutesearchingthewholehouseforit.TheaffordableTrackRevencomeswithadouble﹣sidedadhesive黏合剂soyoucansticktoyourlaptoporunderyourbikeseat.Trackdownandpunishthethieveswhostealyourexpensivethings!TheconvenienceandtheabilitytofindactuallyanyobjectmeansthatTrackRisoneofthemostusefularticlesthatyou'llfindforanyprice.Howeverthebestthingitcangiveispeaceofmindanditdoesn'tgetanybetterthanthat. 1WhatisParagraph2mainlyabout? A.HowtheTrackRworks. B.ThefeaturesoftheTrackR. C.WhytheTrackisinvented. D.TheadvantagesoftheTrackR. 2WhatcantheTrackRhelppeopledo? A.Walktheirpetsnearby. B.Recognizethethives. C.Seektheirmisplacedcar. D.Findthemaparkingplace. 3WhatcanweinferabouttheTrackR? A.It'sfarfromaffordable. B.It'sonsaleworldwide. C.Itcanbeeasilyfolded. D.It'ssmallinsize. 4What'sthebesttitleforthetext? A.TrackR﹣nolimits B.TrackR﹣﹣﹣noworries C.TrackR﹣﹣﹣youritemprotector D.TrackR﹣﹣﹣yourfinancialmanager
某市准备建一个如图所示的综合性休闲广场已知矩形广场的总面积为2000平方米其中阴影部分为通道通道的宽为1米中间的两个小矩形完全相同. 1用矩形的宽x米表示中间的三个矩形的总面积S平方米的函数关系式并给出定义域 2当矩形的宽为何值时S取得最大值并求出最大值.
Haveyoueverwantedtoknowwhatadecoratorwasthinkingwhilechoosingmaterials?1Herearetipsyoushouldknowbeforeyoubuyplantsatthenursery. Anyplantsyoupickwillbeeasiertogrowiftheylikethespaceyou'replantingthemin.Sofirstgetagoodsenseoflight.Isthespotsunnyalldayorisitonlysunnyintheafternoon?Ifthespotdoesn'tseemuchdirectsunlookforshade﹣lovingplants.2Italsoinvitesattackfromdiseaseandpests. 3Afteraheavyraindoesitdryoutafteracoupleofdaysorstaywetforawhile?Plantsthatlikethesoilonthedrysidearerottenwhentheirrootsstaywet.Plantsthatdon'tlikeitdrywillfadeawayiftheydon'tgettodrinkenough.Knowingaboutthesoilhelpsyougrowhealthyplants. Howmuchspacedoyouhave?4Whatlooksliketheperfectplantmightheaburdenifitgrowstoobig.Youhavetoprune修剪itbackeverymonthjusttousethesidewalkorseeoutofwindows. Thelastthingyoushouldknowistoconsideryourownsparetime.Someplantsneedmorecarethanotherswhileothersneedless.5Varietieslikepurpleconeflowerforexampleneeddeadheadingtokeepproducingnewflowersandtopreventalotofyoungplants.Theygrowfinewithoutanycareinashortperiod. A.Howmuchyouwanttowater? B.Afteryouknowwhatthelightislikefocusonthesoil. C.Placingsun﹣loversbeneathatreekeepsthemfromflowering. D.Doyouwonderhowtoshoptherightplantsforyourcourtyard? E.Puttingmatureplantsinasunnyspotresultsinlargerandgreenerleaves. F.Payattentiontotheplants'maturesizeandknowwhatspaceyouhavetofill. G.Thereforeheawarehowmuchtimeyou'rewantingtospendtakingcareofthem.
如图所示是地球的两颗卫量a和b其中b是地球的同步卫星下列说法正确的是
在锐角△ABC中内角ABC的对边分别为abc且=a. 1求角A 2若△ABC的面积为求实数λ的范围.
假定你是李华你想邀请在中国留学的英国好友Peter观看京剧表演但Peter不在家你给他写张留言条内容要点: 1你到Peter家的目的; 2介绍京剧; 3询问什么时候方便再约时间观看. 注意: 1词数100左右; 2可以适当增加细节以使行文连贯; 3开头语和结尾语已为你写出. 参考词汇:quintessence精华精粹;ornate华丽的 DearPeter Yours LiHua.
如图所示轻弹簧的劲度系数为k一端固定在内壁光滑半径为R的半球形容器底部O′处O为球心弹簧另一端与质量为m的A小球相连小球静止于P点OP与水平方向的夹角为θ=30°若换成质量为2m的小球B与弹簧相连小球静止在之间的M点图中没有标出重力加速度为g下列说法正确的是
如图所示水平面上有一半径为R的半圆柱形玻璃砖一束平行光以45°的入射角照射到玻璃砖的上表面已知光在此玻璃砖中的传播速度为c.光在真空中的速度为c求 1圆柱面上光线能够从弧线MP射出的区域所对的圆心角α 2能从圆柱面射出的光线中在玻璃砖中传播的最长时间不考虑反射光线
某同学利用一段长电阻丝测定一节干电池的电动势和内阻接好如图所示的实验装置后将导线的接头O分别连接上电阻丝的abcd四位置并闭合电路测量.电压表电流表均为理想电表 1实验中选择从电阻丝的左端a开始而不是从电阻丝的最右端开始的主要原因是 A.操作简便方便实验 B.防止因电阻过小而烧坏电源保护电路 C.测量更多组数据减小实验误差 D.随机实验从哪端开始都可以 2实验中得到两电表读数如下 经检查电阻丝某处发生断路.根据表格里的数据可推断发生断路位置在填写字母两点之间电源内阻为Ω 3该同学使用的是均匀电阻丝abcd四点等间距在不修复电阻丝的情况下O与电阻丝任意位置连接不可能出现的电表读数是 A.1.15VB.1.30VC.0.24AD.0.35A
Whilestaringoutofthewindowduringaflightnoteveryonewillthinkcarefullyaboutthequestionwhyairplaneshaveroundedwindowsratherthansquareones. Overtheyearsaerospaceengineeringhasmadehugestepsinairplanetechnologymeaningplanescancarrymorepassengersandgofaster.Theplaneshavealsochangedshapetoincreasesafety﹣includingthewindows.Ascommercialairtraveltookoffinthemid﹣20thcenturyairlinecompaniesbegantoflyathigheraltitudestolowertheircost﹣theairdensity密度isloweruptherecreatinglessdrag阻力forairplanes.Howeverhigheraltitudescamewithproblemslikethefacthumanbeingscan'treallysurviveat30000feet.Tomakethatpossiblethecabinwaschangedtoacylindrical圆柱体shapetosupportthepressureinside.Butatfirstplanebuildersleftinthestandardsquarewindowsandthisexpansionmeantdisaster.ThedeHavillandCometcameintofashioninthe1950s.Withaclosedcabinitwasabletogohigherandfasterthanotheraircraft. Howeverwherethere'sacornerthere'saweakspot.Windowshavingfourcornershavefourpotentialweakspotsmakingthemlikelytocrashunderstress﹣suchasairpressure.Bycurvingthewindowthestressthatwouldeventuallybreakthewindowcornerisdistributedandthechanceofitbreakingisreduced.Roundedshapesarealsostrongerandresistdeformation变形andcanthussurvivetheextremedifferencesinpressurebetweentheinsideandoutsideoftheaircraft. Fortunatelydesignersfiguredoutthelackofdesignprettyquick.Nowwehaveniceroundedairplanewindowsthatcanresistthepressureoftravelingaltitude.Itgivesbeingabletogazeoutofyourwindowtotheworldfrom35000feetawholenewoutlookdoesn'tit? 1Whydidairlinesaimtoflyathigheraltitudes? A.Toincreasesafetyoftheplane. B.Tohelptheplanetotakeoff. C.Tosavemoneyforlessdrag. D.Tocarrymorepassengersandgofaster. 2WhatdoestheunderlinedwordsdeHavillandCometinParagraph2referto? A.Aplanet. B.Aband. C.Anaircraft. D.Adesign. 3Whichistheadvantageoftheroundedwindow? A.Itreducesthepossibilityofbreakingup. B.Itweakensthestrengthofairpressure. C.Itincreasestheairpressure. D.Ithelpstosurvivetheextremeweather. 4Wheredoesthistextcomefrom? A.Anewspaperonsafedriving. B.Amagazineonfashiondesign. C.Awebsiteonsurvivalskills. D.Asciencebookonflying.
Haveyoueverspentanafternooninthebackyardmaybegrillingorenjoyingabasketballgamewhensuddenlyyounoticethateverythinggoesquiet?Thereisanoldphrasecalmbeforethestormoftenusedinasituation﹣aquietperiodjustbeforeagreatactivityorexcitement.Accordingtoourownexperienceweknowthereisactuallycalmbeforethestorm.Butwhatcausesthiscalm?Andisitalwayscalmbeforethestorm?Let'shearwhatscientistshavetosay. Aperiodofcalmhappensinaparticularkindofstormthesimplestkindofstorm﹣asingle﹣cellthunderstorm.Inthistypeofthunderstormthereisusuallyonlyonemainupdraftwhichiswarmdampairanddrawnfromplacesneartheground.Stormsneedwarmanddampairasfuelsotheytypicallydrawthatairinfromsurroundingenvironment.Stormscandrawintheairthatfittheirneedfromalldirections﹣evenfromthedirectioninwhichthestormistraveling. Asthewarmdampairispulledintoastormsystemitleavesalow﹣pressurevacuum真空comingafter.Therisingairmeetsthecolddryairthathasalreadyexistedinthestormcloudsthusthetemperatureofthewarmdampairdropsandthewatervapour水蒸汽initchangesintotinydropsthatareapreconditionofrain.Thesedropsaccumulateandbuildonlargerparticleslikedustuntiltheygrowlargeenoughtoformraindrops. Thiswarmdampairkeepsmovingupwardsbutitbecomescooleranddrierduringitstripthroughcloud.Whenitreachesthetopofthecloudtheairgetsspitout被挤出atthetop.Thisairissentrollingoutoverthebigthunderclouds.Fromtheretheairgoesdown.Warmanddryairisrelativelystableandonceitcoversaregionthatairinturncausesthecalmbeforeastorm. Mostthunderstormsthoughdon'tstartwithcalm.That'sbecausemostareactuallygroupsofstormswithcomplexwindpatterns.There'ssomuchairmovingupanddownstormgroupsthatthecalmbeforethestormneverhappens.Insteadbeforethestormitmightbereallywindy! 1Whichbestfitsthedescriptionofaparticularkindofstorm? A.Astormwithairdrawnfromeverydirection. B.Athunderstormwithoutstrongwinds. C.Athunderstormwithasingleshape. D.Astormfueledbymovingairfromtheground. 2WhatdoestheunderlinedworditinParagraph3referto? A.Coldanddryair. B.Warmanddampair. C.Coldanddampair. D.Warmanddryair. 3Whichdoesthewritermostlikelyagreeto? A.Presenceofthecalmreliesonstableair. B.Stormhappenswithoutairmovingupanddown. C.Thedriertheairisthebiggerthestormwillbe. D.Notallthunderstormsstartwiththecalm. 4Whatisthepassagemainlyabout? A.Causesandeffectsofaheavystorm. B.Anexplanationofthecalmbeforeastorm. C.Apersonalexperienceofaheavystorm. D.Abriefdescriptionofapeacefulstorm.
若a>b则的最小值为.
IntheUKwethrowawayabout2.5billiondisposable一次性的coffeecupseveryyear.Thebedthingisthelayerofpolyethylenethatdoesn'tletthecupleakandthelidwhichismostoftenmadeofpolystyrene.Thismakesthemabitofabarrier.Asaresultmostofthecupsendupinlandfillthoughtheyarerecyclableintheory. Butthereareeffortsunderwaytosettlethisproblem.OnecompanyBiomeBioplasticshascomeupwithafullyrecyclablecupthatusesnaturalmaterialssuchaspotatopowder.Mr.Minesitsgeneralmanagerbelievesthatthisisthefirsttimethatbioplastichasbeenusedfordisposablecupsandlidsthathavetodealwithhotliquid.Andthey'restillfullyrecyclable.AnothersolutionhasbeenputforwardbyFrugalpac.Theyhavepatentedacupwithalightly﹣attached一lacticinn.一layer.ThiscanbeeasilyseparatedduringtherecyclingandoffersamorepracticalsolutionthanchangingourcurrentrecyclinghabitssaysFrugal﹣pac'sfounderMartinMyerscough. SafiaQureshisaysIndiahasprovidedtheinspirationforhersolution.SheputsforwardthatweusereturnableandreusablecupswhicharetrackedandcollectedbyhercompanyCupClub.Theywillberesponsibleforcollectingwashingandredistributingthecleancupstoparticipatingtradesmen.OnefinalcreativeapproachcomesfromCupffee.Theyhavecombinedgrainstoformacupwhichcanbeconsumedoncethedrinkisfinished.Itcanholdacoffeeforupto40minutesandwillbiodegrade生物降解withinweeks. Whetheranyoftheseideasisaperfectfitforthisdisposableproblemonlytimewilltell.Allitmayrequireisalittlemorethinkingoutsidethebox. 1WhatdoweknowaboutthedisposablecoffeecupsintheUK? A.Fewarerecycled. B.Theyarestronglydesigned. C.Theyhavequalityproblems. D.Mostareenvironmentallyfriendly. 2WhatcanweinferaboutFrugalpac'scus? A.Theyareeasytopatent. B.Theyarepartlyrecyclable. C.Theyenjoygreatpopularity. D.Theysuittraditionalrecyclinghabits. 3InwhatwayareCupffee'scupsdifferentfromothers? A.Theyaretime﹣consumingtoproduce. B.Theycanbreakdowninstantly. C.Theyaretoeveryone'staste. D.Theycanbeeatable. 4Whatcanbeasuitabletitleforthetext? A.BadHabitsofUsingCoffeeCups B.ProblemwithCurrentCoffeeCups C.CreativeWaystoRecycleCoffeeCups D.ReasonsforProducingNew﹣styleCoffeeCups
NatalieTraylingisafamousstreetartistinMelbourne.Atfirstthosewhohappenedtopassbyherandsparesomechangedidn'tevenrealizewhatamusicalgeniuswasplaying.TheemotionaltunewasnotonlymasterfullyplayedbutalsocomposedbyNatalieherselfwhenshewasonly14.Graduallyaslongassheappearspeoplewillstopabsorbedinhermusic.Hermusicmakesyouthinkaboutcalmnessthegoodthingsinlifeandnevergivingup. Butwhatpeopledonotknowisthatbehindthebeautifulmusicoftheoldwomanitisfullofbitterness.Attheageof12shewonamusicscholarshipatSantaMariaCollege.At15sheknockedbackascholarshiptotheRoyalAcademyofMusicinLondonbecauseherparentscouldn'tpaynon﹣tuitioncosts.WhensheleftschoolshetaughtpianoatSantaMaria.LatershemetherhusbandDenis.Theyhadfourchildrenbutthetwoofthemdied.In1984Denisaskedforadivorce.Natalie'ssonNathanwasgivenmedicationfordepression.NatalielivedeitheroutdoorsinRoyalParkorinboardinghousesfornineyears.Inlate2003Nataliecollapsedwithanaemia贫血andwashospitalizedforsixmonths. ForhalfacenturyNataliehasbeenteasedbyfate.Butevensoshenevergaveupherloveformusic.Whenaskedwhythemusicwassoimportanttohershesaid:Musiciseverything.Idofeelpartofit.Thewholeworldismusic. WhenNataliewentontheInternetshebecameasignofMelbourne.Peopleareimpressedbyherpersistenceindreamsandtheoptimismoflife.Nowsheisnolongerwanderingaround.ShecanplaythepianoatanytimebutaslongastheweatherisgoodshewillwalktothestreetsofMelbourneandplayatouchingmelodyfortherushofthecity. 1WhyisNatalie'smusicsotouchingtothepassers﹣by? A.Itisfullofbitterness. B.Shecomposeditherself. C.It'sareflectionofherownlife. D.Itremindsofthebeautyoflife. 2WhichofthefollowingcanreplacetheunderlinedwordknockedbackinParagraph2? A.gaveup B.obtained C.accepted D.wasawarded 3WhatdoesmusicmeantoNatalie? A.It'shertalent. B.It'sthesourceofhermisfortune. C.Itispartofherlife. D.It'sawaytoearnaliving. 4Whatdoestheauthortrytotellus? A.Natalieisamusicalgenius. B.Lifeisnoteasyforeveryone. C.Nevergiveuphalfway. D.Nataliehasastrongandbraveheart.
如图所示竖直放置的光滑圆柱形绝热气缸上端开口有一质量m=10kg横截面积S=10cm2的绝热活塞将一定质量的理想气体封闭在气缸内在气缸内距缸底h=0.2m处有体积可忽略的卡环ab使活塞只能向上滑动.开始时活塞搁在ab上缸内气体的压强等于大气压强温度为T0=200K.现通过内部电热丝缓慢加热气缸内气体直至活塞恰好离开ab.已知大气压强p0=1.0×105Pa.g取10m/s2求 1活塞恰要离开ab时缸内气体的压强p1 2当活塞缓慢上升△h=0.1m时活塞未滑出气缸缸内气体的温度出T为多少 3若从开始加热到活塞缓慢上升△h=0.1m的全过程中电阳丝放热52J求气体内能的变化量△U
InmanyplaceslikeBritainandItalyifyouleavethehousewithoutyourwalletyou'llbeinatoughsituationallday.ButinChinayoucanenjoyyourdayjust1asmartphone. TheotherdayIsetout2seehowfaraphonewouldgetmeinthecountry'scapital.AdmittedlyIwassurprisedtodiscoverhow3convenienceitwas. IusedmyphonetocallataxitomeetmyChinesefriendGuYu4wouldguidemetogetaroundBeijing.Wepaidforbreakfastby5scanaQRcodeonthewindowofarestaurantsellingjianbingoneofChina'smostpopularstreetbreakfasts.Mypurchasecost6yuanand6takejustafewseconds.Atanearbycoffeeshop7itownerscannedaQRcodeonmyphone.AswesippedourcoffeeGuYupaidherhouseholdwaterbill.Sheusedthesamesimpleprocesstopayotherbillsandevenherrent.Wealsopaidbyphoneformovieticketstakeoutfoodshoppingandfor8deliver. IhaveknownfromGuYuthatfromtinystreetstandstolargechains9hugenumberofpeopleacceptmobilepayment10mostthroughpopularappsAlipayandWeChat.
在同一条笔直的公路上行驶的三辆汽车abc它们的x﹣t图象如图所示汽车a对应的图象是条抛物线其顶点坐标为010下列说法正确的是
如图为测量某山峰的高度即OP的长选择与O在同一水平面上的AB为观测点.在A处测得山顶P的仰角为45°在B处测得山顶P的仰角为60°.若AB=30米∠AOB=30°则山峰的高为米.
在某一稳定轨道运行的空间站中物体处于完全失重状态.如图所示的均匀螺旋轨道竖直放置整个轨道光滑PQ点分别对应螺旋轨道中两个圆周的最高点对应的圆周运动轨道半径分别为R和rR>r.宇航员让一小球以一定的速度v滑上轨道下列说法正确的是
Helicopterparentingreferstoastyleofparentswhoareoverfocusedontheirchildren. 1Forexampleitcanincreasefeelingsofloveandacceptance.Howeverhelicopterparentingmaybeharmfultochildren'sdevelopmentinthefollowingways. Decreasedconfidenceandselfesteem自尊.Themessagetheparents'overinvolvementsendstokidsismyparentsdon'ttrustmetodothisonmyown.2 Increasedanxiety.AstudyfromtheUniversityofMaryWashingtonhasshownthatoverparentingisassociatedwithhigherlevelsofchildanxietyanddepression. Undevelopedproblemsolvingskills.Ifparentsarealwaystheretocleanupachild'smessorpreventtheprobleminthefirstplacehowdoesthechildeverlearntodealwithlossdisappointmentorfailure?3 Strengthenedsenseofentitlement权利.Childrenwhohavealwayshadtheirsocialacademicandathleticlivesadjustedbytheirparentstobestfittheirneedscanbecomeaccustomedtoalwayshavingtheirwayandthustheydevelopasenseofentitlement. 4Parentswhoalwaystieshoesclearplatesandpacklunchesevenafterchildrenareabletodothetaskspreventtheirchildrenfrommasteringtheselifeskillsthemselves. Soparentsshouldletchildrenstruggleallowthemtobedisappointedandwhenfailureoccurshelpthemtoworkthroughit.5Remember:takingonestepbackfromsolvingchildren'sproblemswillhelpbuildtheindependentandselfconfidentkids. A.Weakenedlifeskills. B.Damagedlifeexperiences. C.Andthisdistrustleadstoalackofconfidence. D.Helicopterparentinghasmanybenefitsforchildren. E.Parentsshouldalsoletchildrendotaskstheyarephysicallyandmentallyabletodo. F.Makingyour3yearold'sbedsoundsreasonablewhilemakingyour13yearold'sbeddoesn't. G.Studiesfoundhelicopterparentingcanmakechildrenfeellessableindealingwiththestressesoflifeontheirown.
假定英语课上老师要求同桌之间交换修改作文请你修改你同桌写的以下作文.文中共有10处语言错误每句中最多有两处.每处错误仅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Ʌ并在其下面写出该加的词. 刪除:把多余的词用斜线\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.每处错误及其修改均仅限一词 2.只允许修改10处多者从第11处起不计分 Beingaseniorstudent.IlikeEnglishmorethananyothersubject.BesideshavingEnglishlessonsatschoolIgototheEnglishCornerintheparkwhereisnearmyhomeatSaturdaymornings.ItsetuptwoyearsagowiththepurposeofhelpingstudentsmakeaprogressinEnglish.Manyhighschoolstudentsregulargatherhere.Sometimes.somecollegestudentsorevenforeignfriendsarepresentattheEnglishCorner.TherewepractisespokenEnglishtalkedaboutwhatweareinterestedinintroducingourexperienceinlearningEnglishandsoon.IhadgreatlyimprovedinEnglishsinceIattendedthemforthefirsttime.
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