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如图，在正三棱柱ABC﹣A1B1C1中，已知D，E分别为BC，B1C1的中点，点F在棱CC1上，且DE⊥C1D．求证： （1）直线A1E∥平面ADC1； （2）平面A1EF⊥平面ADC1．
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高二上学期数学《》真题及答案
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已知三棱柱ABC—A1B1C1的侧棱与底面边长都相等A1在底面ABC内的射影为△ABC的中心则AB1
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如图在正三棱柱ABC-A1B1C1中E.F.分别为BB1AC的中点.1求证BF∥平面A1EC2求证平
如图三棱柱ABC﹣A1B1C1中各棱长均相等D.E.F.分别为棱ABBCA1C1的中点.Ⅰ证明EF∥
如图在直三棱柱ABC—A1B1C1中AA1=BC=AB=2AB⊥BC求二面角B1—A1C—C1的大小
如图已知直三棱柱ABC-A.1B.1C.1中AB＝ACD.E.分别为BCCC1中点BC1⊥B.1D.
如图在正三棱柱ABC-A1B1C1中E.F.分别为线段A1AC1B的中点求证EF∥平面ABC.第9题
如图△ABC的顶点坐标分别为A.13B.42C.21.作出与△ABC关于x轴对称的△A1B1C1并写
已知三棱柱ABC—A1B1C1的侧棱与底面边长都相等A1在底面ABC内的射影为△ABC的中心则AB
A
B
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如图10-22在正三棱柱ABC—A1B1C1中AB=3AA1=4M.为AA1的中点P.是BC上一点且
已知三棱柱ABC—A1B1C1的侧棱与底面边长都相等A1在底面ABC内的射影为△ABC的中心则AB1
A
B
C
D
如图在直三棱柱ABC—A1B1C1中AA1=BC=AB=2AB⊥BC求二面角B1—A1C—C1的大小
如图直三棱柱ABC—A1B1C1中AB⊥ACDE分别为AA1B1C的中点DE⊥平面BCC1．1证明A
如图直三棱柱ABC—A1B1C1中AB⊥ACDE分别为AA1B1C的中点DE⊥平面BCC1．1证明A
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能够说明“在某个区间ab内如果函数y＝fx在这个区间内单调递增那么f'x＞0恒成立”是假命题的一个函数是．写出函数表达式和区间
You'vegotyourfancynewsuitcaseandyou'rereadytotakeitwithyouonyourtravelsacrosstheglobe. Yougettotheairportquicklymovingthroughthecrowdsontheunevenpavementrushingtocheckin.Thenyourheartsinkswhenyourealizeyournewsuitcasehasgotaseriouscaseofthewobbles摇晃. Whydoesthishappen? ScientistsfromtheUniversiteParis﹣DiderotinFranceinvestigatedthismatterandpublishedtheirfindingsinthesciencejournalProceedingsoftheRoyalSocietyA.Theyalsosuggestedsomesolutionstoovercomethismodern﹣dayproblem. Tolearnmoreabouttheissuetheyputasuitcaseonatreadmill跑步机andobservedwhathappened. Itwassoonnotedthatthewobblewasactuallyaresultofrepeatedactionsthatcausedthesuitcasetoswayfromsidetoside.Theydiscoveredthatifoneofthewheelsencounteredanobstaclesuchasasmallbumpitjumpedintotheairforjustamomentandthenbangedbackdowntotheground.Thatsecondactioncausedtheoppositewheeltoliftoffthegroundandthentobangbackdowncausingthefirsttoliftagainandsoon.Thisswayingincreasedastheluggagewaspulledalong. Thesuitcaseisafunwaytotackletheproblembutthestudywouldbethesameforanytrolleywithtwowheelsorblades桨叶SylvainCourrechduPontleadauthorofthestudytoldBBCNews.Soitwillbethesameforacaravan大篷车ormaybealsoforairplanes. Insteadofslowingdownwhenweseearockypartofthepaththescientistsrecommendeddoingtheexactoppositeandspeedingup.Thisisbecausegoingfastergivesthewheelslesstimetoriseandfallpreventingthecasefromswaying.Theyalsosaidthatreducingtheangleofthesuitcasebyloweringitshandletothegroundwouldhelpkeepitsteady. ThesefindingscouldhelpresearcherssimulateanddesignbetterrollingsuitcasesandotherpulledtrolleyssuchastowedtrailersCourrechduPontadded. Withthesemasterminds智者workingonperfectingoursuitcaseproblemswobblyluggagemaysoonbeathingofhistoryleavingustoenjoyourtravels. 1Themainpurposeofthefirsttwoparagraphsisto. A.showtheimportanceofagoodwheeledsuitcasefortravel B.leaduptothewobblingproblemofwheeledsuitcases C.describehowunstablewheeledsuitcasescanbe D.showthatwobblingcancausewheeledsuitcasestostopworking 2Accordingtothescientistswhenasuitcasemeetswithanobstacle. A.theswayingwillstopforamoment B.itstwowheelswilljumpintotheairatthesametime C.evenasmallobstaclecanleadtoaseriousdamage D.thereisaseriesofrepeatedactionsleadingtotheswaying 3Whatcanbedonetokeepasuitcasesteadyonanunevenpathaccordingtothetext? A.Slowdown. B.Pullthesuitcaseatafasterspeed. C.Raisethehandleofthesuitcase. D.Increasetheangleofthesuitcase. 4Accordingtothearticlethefindingscould. A.helpimprovethedesignofsuitcases B.solvethewobbleofsuitcasescompletely C.behelpfulintheadvancementoftreadmills D.beusedtodevelopbladesforboats
为调查某公司五类机器的销售情况该公司随机收集了一个月销售的有关数据公司规定同一类机器销售价格相同经分类整理得到下表 利润率是指一台机器销售价格减去出厂价格得到的利润与该机器销售价格的比值． Ⅰ从该公司本月卖出的机器中随机选一台求这台机器利润率高于0.2的概率 Ⅱ从该公司本月卖出的销售单价为20万元的机器中随机选取2台求这两台机器的利润率不同的概率 Ⅲ假设每类机器利润率不变销售一台第一类机器获利x1万元销售一台第二类机器获利x2万元…销售一台第五类机器获利x5依据上表统计数据随机销售一台机器获利的期望为Ex设＝试判断Ex与的大小．结论不要求证明
Asimplelifemeansgettingridofmanyofthethingsyoudosothatyoucanspendmoretimewithpeopleyouloveanddothethingsyoulove.1It'softenajourneyoftwostepsforwardandonebackward. Evaluateyourtime.2Whatthingsdoyoudofromthetimeyouwakeuptothetimeyougotosleep?Makealistandevaluatewhetherthey'reinlinewithyourpriorities.Ifnotremovethemandfocusonwhat'simportant.Redesignyourday. Limityourcommunications.OurlivesthesedaysarefilledwithavastflowofcommunicationsemailcellphonespapermailTwitterforumsandmore.3Insteadsetalimitonyourcommunicationsonlydealwithemailsatcertaintimesoftheday.Limitphonecallstocertaintimestoo.Itisthesamewithothercommunications.Setascheduleandsticktoit. Trylivingwithoutacar.OKthisisn'tsomethingI'vedonebutmanyothershave.4Walkbikeortakepublictransportation.Itreducesexpensesandgivesyoutimetothink.Acarisalsoverycomplicatedneedingnotonlycarpaymentsbutinsurancemaintenancerepairsgasandmore. 5Ifyouridyourhomeofstuffyoumightfindyoudon'tneedsomuchspace.I'mnotsayingyoushouldliveonaboatalthoughIknowsomepeoplewhohappilydosobutifyoucanbecomfortableinasmallerhomeitwillnotonlybelessexpensivebuteasiertomaintainandgreatlysimplifyyourlife. A.Considerasmallerhome. B.Haveaplaceforeverything. C.Howdoyouspendyourday? D.It'ssomethingIwoulddoifIdidn'thavekids. E.Theycantakeupyourwholedayifyouletthembe. F.Howevergettingtosimplicityisn'talwaysasimpleprocess. G.Mostpeopledon'tknowwhatenoughisandthustheykeepbuyingmore.
WilliamButlerYeatsamostfamousIrishwriterwasborninDublinonJune131865.Hischildhood1theharmonythatwas2ofahappyfamily.LaterYeatsshockedhisfamilybysayingthatherememberedlittleofchildhoodbutitspain.Infacthe3excellenttasteinartfromhisfamily﹣bothhisfatherandhisbrotherwerepainters.Buthefinally4literature5dramaandpoetry. Yeatshadstrong6inthecomingofnewartisticmovements.Hesethimselfthe7taskinfoundinganIrishnationaltheatreinthelate1890s.Hisearlytheatricalexperiments8werenotreceived9atthebeginning.Hedidn'tloseheartandfinallyenjoyed10inhispoeticaldrama. 11withhisdramaticworksYeats'spoemsattractmuch12notice.Thesubjectmatterincludeslovenaturehistorytimeandaging.ThoughYeatsgenerallyreliedonverytraditionalformshebroughtmodern13tothem.Ashisliterarylife14hispoetrygrewfinerandricherwhichledhimtoworldwide15. Hehadnot16amajorpubliclife17winningtheNobelPrizein1923.Yethecontinuedwritingalmosttotheendofhislife.HadYeatsstoppedwritingatage40hewouldprobablynowbe18asaminorpoetforthereisnootherexampleinliteraryhistoryofapoetwho19hisgreatestworksbetweentheagesof50and75.AfterYeats'sdeathin1939W.H.Audenwroteamongothersthefollowinglines Earthreceivean20guest WilliamYeatsislaidtorest. LettheIrishvessel船lie. Emptiedofitspoetry. 1A.held B.lacked C.expected D.desired 2A.typical B.special C.awkward D.capable 3A.inherited B.developed C.abandoned D.formed 4A.carriedon B.decidedon C.puton D.basedon 5A.regularly B.instantly C.particularly D.finally 6A.desire B.energy C.access D.faith 7A.fresh B.stupid C.small D.difficult 8A.therefore B.however C.besides D.furthermore 9A.possibly B.honorably C.favorably D.doubtfully 10A.failure B.fame C.pleasure D.success 11A.Connected B.Occupied C.Compared D.Tired 12A.admiring B.amusing C.amazing D.envying 13A.potential B.sensibility C.possibility D.benefit 14A.finished B.produced C.created D.progressed 15A.praise B.spread C.recognition D.assessment 16A.enjoyed B.accepted C.purchased D.taken 17A.before B.since C.until D.after 18A.respected B.admired C.valued D.favored 19A.prohibits B.attempts C.recommends D.produces 20A.appealed B.advocated C.advanced D.honored
MysummerholswrCWOT.B4WEUSED2go2NY2CmybrohisGF&thr3﹣@KIDSFTF.ILNYitsgr8. Canyouunderstandthissentence?Ifyoucan'tdon'tfeeltoobadneithercouldthemiddleschoolteacherinEnglandwhoreceivedthisashomework.ThisisNetspeakthelanguageofcomputerizedcommunicationfoundontheInternetorcellphones.Tonewcomersitcanlooklikeacompletelyforeignlanguage. Schoolteachersandparentssaythisnewformofwritingisharming破坏theEnglishlanguage.Increasingspellingandgrammaticalmistakescanbeseeninstudents'writing.Theyfearthelanguagecouldbecomecorrupted面目全非的. Everyoneshouldjustrelaxsaylinguists语言学家.TheybelieveNetspeakisinfactmoreofagoodthing.DavidCrystalfromtheUniversityofWalesarguesthatNetspeakandInternetcreateanewlanguageuseandthealmostlostartofdiarywritinghasbeenpickedupagain.GeoffreyNurnbergfromStanfordUniversityagrees.Peoplegetbetteratwritingbywritinghesays.Kidswhoarenowdoingtextmessaginge﹣mailandinstantmessageswillwriteatleastaswellasandpossiblybetterthantheirparents. LinguistJamesMilroysaysforcenturiesitisbelievedwithoutexceptionthatyoungpeopleareharmingthelanguage.Andwhentoday'steenagersbecometomorrow'sparentstheytoowillthinkthisway.Milroyarguesthatlanguagesdonotandcannotbecomecorruptedtheysimplychangetomeetthenewneeds. HoweverNetspeakersdoagreethatitisimportanttoteachyoungpeoplehowtospeakandwriteStandardEnglish.CynthiaMcVeysaysIcanunderstandNetspeakworriesteachersandit'simportantthattheytelltheirpupilsthattextmessagingisforfunbutthatlearningtowriteproperEnglishisamustfortheirfuture. 1Whatisthepurposeofthefirstparagraph? A.Togivethemainidea. B.Toraiseaquestion. C.Tocompareanexample. D.Toleadinthetopic. 2WhocanunderstandtheNetspeakinEngland? A.Middleschoolteachers. B.Parents. C.Linguistics. D.Teenagers. 3WhobelievesNetspeakuserscanhelpimprovewriting? A.CynthiaMcVey B.DavidCrystal C.GeoffreyNurnberg D.JamesMilroy 4What'sJamesMilroy'sattitudetowardNetspeak? A.Positive. B.Negative. C.Doubtful. D.Worried. 5Whatcanbethebesttitleforthepassage? A.NetspeaktheLanguageontheInternet B.IsNetspeakHelpfulinLanguageLearning? C.IsNetspeakHarmingtheEnglishLanguage? D.NetspeakAdvantagesandDisadvantages
TwoofthesaddestwordsintheEnglishlanguageareifonly.Ilivemylifewiththegoalofneverhavingtosaythosewordsbecausetheyconveyregretlostopportunitiesmistakesanddisappointment. MyfatherisfamousinourfamilyforsayingTaketheextraminutetodoitright.Ialwaystrytolivebytheextraminuterule.WhenmychildrenwereyoungandlikelytocauseaccidentsIalwaysthoughtaboutwhatIcoulddotoavoidanifonlymomentwhetheritwassomethingminorlikemovingacupfullofhotcoffeeawayfromtheedgeofacounterorsomethingthatrequiredalittlemoreworksuchastapingpadding衬垫ontothesharpcornersofaglasscoffeetable. Idon'tonlyavoidthoseifonlymomentswhenitcomestosafety.It'sequallyimportanttoavoidifonlyinourpersonalrelationships.WeallknowpeoplewholostalovedoneandregrettedthattheyhadforegoneanopportunitytosayIloveyouorIforgiveyou.WhenmyfatherannouncedhewasgoingtotheeyedoctoracrossfrommyofficeonGoodFridayItoldhimthatitwasaholidayformycompanyandIwouldn'tbehere.ButthenIthoughtaboutthefactthathe's84yearsoldandIrealizedthatIshouldn'tgiveupanopportunitytoseehim.IcalledhimandtoldhimIhaddecidedtogotoworkonmydayoffafterall. IknowtherewillstillbeoccasionswhenIhavetosayifonlyaboutsomethingbutmylifeisdefinitelybetterbecauseofmypolicyofdoingeverythingpossibletoavoidthateventuality.AndeventhoughittakesanextraminutetodosomethingrightoritoccasionallytakesanhourortwoinmybusyscheduletomakeapersonalconnectionIknowthatI'mdoingtherightthing.I'mbuyingmyselfpeaceofmindandthat'sthebestkindofinsuranceformyemotionalwell﹣being. 1Whichofthefollowingisanexampleoftheextraminuterule? A.Startthecarthemomenteveryoneisseated. B.Leavetheroomforaminutewiththeironworking. C.Moveanobjectoutofthewaybeforeittripssomeone. D.Waitforanextraminutesothatthesteaktastesbetter. 2TheauthordecidedtogotoherofficeonGoodFridayto. A.meetherfatherwhowasalreadyanoldman B.keepherappointmentwiththeeyedoctor C.joinintheholidaycelebrationofthecompany D.finishherworkbeforethedeadlineapproached 3TheunderlinedwordforegoneinParagraph3isclosestinmeaningto. A.wasted B.lacked C.avoided D.abandoned 4Whatisthebesttitleforthepassage? A.TheTwoSaddestWords B.TheEmotionalWell﹣being C.TheMostUsefulRule D.ThePeaceofMind
SeveralweeksagoourheadmasterMr.GauditoldusthatourschoolhadbeenchosentocompeteonSmartAleck﹣agameshowwhichmybestfriendCarlaandIbothlove.Carlahasagoodimagination1Iknowalotofhistory.Sowethoughtwe'dbegood2fortheteam. AfewdayslaterMr.Gaudiheldameetingwitheveryoneinterestedinthe3.HetoldusthatSmartAleckusesafivememberteam.Healsosaidthatthreemorepeoplewouldbeneededasbackup替补.4fourtimesthatmanystudentswereatthemeeting.SoMr.Gaudisaidwewouldhavea5amongallthestudentspresentandthetop6scorerswouldbecometheteamandthebackup.Everybodyagreedthatthiswasa7waytodecide. Yesterdayallofthehopefulswenttothedininghallafterschool.Wewouldhaveto8thestartingline﹣up阵容.Mr.Gaudiactedasthe9.Afteracoupleofhoursallthe10ontheteamweresetexceptone.CarlaandI11forthatlastposition.Wehadtoholdaone﹣on﹣onecompetition12thetwoofus.Thewinnerwouldbeontheteamandtheloserwouldbethe13. Midwaythroughourtwo﹣personcompetitionIwasstartingtopullahead.14IsawthelookonCarla'sface.IwaitedforasecondandknewwhatIhadtodo.AsmuchasIwantedtobeonSmartAleckCarlawanted15evenmore.SostartingwithmynextquestionIheldbackandletCarla16justbyalittlebit.Herexpressionasshe17shewouldbeontheshowmadeupformynotbeingontheteam.AndsinceIwillgoasbackupI'llstillhavethe18ofseeingtheshowupclose. WasI19bynottryingashardasIcould?Idon'tthinkso.NoonenoticedandCarlaandIdidn't20it.Itwon'thurttheteambecauseCarlawillbeaverygoodcompetitorontherealshow.Ithinkthatmakingmybestfriendhappywastherightthingtodo. 1A.but B.or C.so D.and 2A.pairs B.choices C.leaders D.fans 3A.course B.work C.play D.show 4A.Luckily B.Unluckily C.Importantly D.Hopefully 5A.direction B.discussion C.competition D.conversation 6A.five B.three C.two D.eight 7A.special B.hard C.funny D.fair 8A.decide B.draw C.push D.make 9A.headmaster B.coach C.host D.headteacher 10A.places B.rules C.names D.orders 11A.tied B.clapped C.cried D.returned 12A.of B.on C.between D.among 13A.backup B.audience C.cheerleader D.member 14A.Still B.Never C.Then D.Again 15A.us B.it C.me D.her 16A.wait B.turn C.move D.win 17A.accepted B.realized C.considered D.refused 18A.laughter B.sadness C.fun D.change 19A.coming B.refusing C.helping D.cheating 20A.mean B.plan C.regret D.say
在△ABC中角ABC的对边分别为abca＝3． Ⅰ求c的值 Ⅱ若D为BC边上的点并且求∠ADB．
假如你是李华你的英国笔友Peter来信说近期要来北京希望你为他设计一个旅行计划推荐一些有中国特色的活动.请根据以下提示写一封回信.内容要点 TravelPlan 注意1.开头语和结束语已经为你写好不计入总词数2.可适当增加细节以使行文连贯 3.文中不能出现考生真实个人信息 4.词数100左右. DearPeter I'mhappytohearyou'recomingtoBeijing. Lookingforwardtomeetingyousoon! Yours LiHua
Inoneofmycollegeclasseswewererequiredtodoanactofkindness.Myprojectincluded1lunchforanelderlyperson.WhenI2theelderlypersonwiththefoodIcookeditnever3tomethatitwouldresultinanewfriendshipandthediscoveryofa4. ThepersonIvisitedwasBillwhowasunableto5much.Anursecameregularlytohelphimmovetoandfromthewheelchairbecausehehasno6.Billsaidhewasdelightedtoseemeanditwasa7forhimtoeatamealwithmebecauseheusuallyeats8.Hesaidthefoodwasgreatbutheenjoyedhaving9evenmorethanthefood. Billhadhada10lifewhenworkingontherailroadandhadmany11storiestotellabouthistravelstomanyplaces.Iwas12atripbecauseofhisstories.Ihadonce13abouttravelingbytrain.HoweverIwould14begoingbytrainaftermeetingBill. Perhapsthebiggest15ofthisprojectwasthatIsuddenlyrealizedthatIam16ofworkingwiththeelderly.Spendingtimewiththemwasfun﹣theyhavesomuchlifeexperienceto17.OntheonehandIamagood18.Ontheotherhandolderpeoplewantsomeonetoknowtheirinnerworldsoitisaperfect19.Idecidedtofocusmystudiesonthe20.HopefullyinthefutureIwillworkwiththemtohelpevenmorepeoplelikeBill. 1A.buying B.delivering C.packing D.preparing 2A.calledon B.cameacross C.pickedup D.turnedto 3A.happened B.appealed C.occurred D.proved 4A.travelplan B.careerpath C.holidaydestination D.cookingskill 5A.talk B.eat C.sit D.walk 6A.money B.relatives C.neighbours D.time 7A.treat B.fancy C.privilege D.waste 8A.slowly B.little C.alone D.unhappily 9A.family B.company C.fun D.health 10A.painful B.hopeful C.peaceful D.colorful 11A.adventurous B.fresh C.absorbing D.satisfying 12A.intending B.pretending C.allowing D.requiring 13A.argued B.hesitated C.thought D.cared 14A.unbelievably B.undoubtedly C.unexpectedly D.unhurriedly 15A.aim B.impression C.problem D.bonus 16A.aware B.proud C.fond D.certain 17A.share B.discuss C.treasure D.gain 18A.student B.cook C.learner D.listener 19A.choice B.deal C.match D.game 20A.old B.poor C.disabled D.homeless
Theideaofturningrecycledplasticbottlesintoclothingisnotnew.Duringthelastfiveyearsalargenumberofclothingcompaniesbusinessesandenvironmentalorganizationshavestartedturningplasticsintofabrictodealwithplasticpollution.Butthere'saproblemwiththismethod.Researchnowshowsthatmicrofiberscouldbethebiggestsourceofplasticinthesea. Dr.MarkBrowneinSantaBarbaraCaliforniahasbeenstudyingplasticpollutionandmicrofibersfor10yearsnow.Heexplainsthateverytimesyntheticclothesgointoawashingmachinealargenumberofplasticfibersfalloff.Mostwashingmachinescan'tcollectthesemicrofibers.Soeverytimethewatergetsoutofawashingmachinemicrofibersareenteringthesewersandfinallyendupinthesea. In2011Brownewroteapaperstatingthatasinglepieceofsynthetic合成的clothingcanproducemorethan1900fibersperwash.Brownecollectedsamplesfromseawaterandfreshwatersitesaroundtheworldandusedaspecialwaytoexamineeachsample.Hediscoveredthateverysinglewatersamplecontainedmicrofibers. Thisisbadnewsforanumberofreasons.Plasticcancauseharmtosealifewheneaten.Studieshavealsoshownthatplasticcanabsorbotherpollutants. Basedonthisevidenceitmayseemsurprisingthatcompaniesandorganizationshavechosentoturnplasticwasteintoclothingasanenvironmentalsolution.EventhoughthesciencehasbeenaroundforawhileBrowneexplainsthathe'shadadifficulttimegettingcompaniestolisten.Whenheaskedwell﹣knownclothingcompaniestosupportBenignbyDesign﹣hisresearchprojectthatseekstogetclothesthathaveabadeffectonhumansandtheenvironmentoutofthemarketBrownedidn'tgetasatisfyinganswer.Onlyonewomen'sclothingcompanyEileenFisherofferedBrownefunding. 1Whathashappenedduringthepastfiveyears? A.Fabrichasbecomemuchstronger. B.Plasticpollutionhasbeenlessserious. C.Manyplasticbottleshavebeenreused. D.Microfibershavebeengreatlyimproved. 2WhatdoesBrownethinkofwashingsyntheticclothes? A.Itisaddingmicrofiberstotheclothes. B.Itisworseningenvironmentalproblems. C.Itismakingsyntheticclotheslastlonger. D.Itisdoinggreatdamagetowashingmachines. 3WhatcanbeinferredaboutBrowne'sBenignbyDesignresearchproject? A.Ithasachievedgreatsuccess. B.Ithasn'tgotanythingdone. C.Itisknowntoveryfewpeople. D.Itisfacingsomedifficulties. 4What'sthebesttitleforthetext? A.It'simportanttolearntorecycle B.It'snevereasytosolvepollutionproblems C.Recycledplasticclothingsolutionorpollution? D.Arehumanbeingsmovingforwardorbackward?
ManypeoplebelievethatthereissometruthinthesayingLaughteristhebestmedicine.1Laughterhelpsrelievepainstrengthentheimmunesystemandreducestress.Laughterstimulates激发hormoneswhichmakeusfeelhappy.Laughteralsoincreasestheflowofbloodthroughoutthebodyandhasbenefitswhicharesimilartotheonesyougetbydoingexercise. 2Childrenexposedtofunnyfilmsandcartoonsbeforemajormedicalproceduresareabletocopebetterwithpainandanxiety.3.Theseareprofessionalclownswhoaresenttohospitalsandwardstoentertainanddistractsickchildren. Laughtertherapyhasbecomeverypopularinrecentyearsandasaresultmoreandmorelaughterclubsarestartingtoopenupincitiesandtownsallovertheworld.Atalaughtersessionatrainedtherapistinstructsthegrouptoperformaseriesofexerciseswhicharedesignedtoproducelaughter.4Andittakesthemsometimetogetridoftheirinhibitions心理抑制.Theymightevenstartoffwithfakelaughterbutthisdoesn'tmatterbecauseourbodiescan'ttellthedifferenceandtheresultsarethesame.Moreoverlaughteriscontagious传染的.5 Sonexttimeyoufeelillstressedoutordepressedtrywatchingafunnyfilmortryrememberinganamusingincidentinyourlife.Youwillsoonfeelbetter. A.Ifonepersonstartsgigglingitisunavoidablethateveryoneelsewillbedrawnin. B.Laughterhelpsyoufocus. C.Thisfindinghasledtoso﹣calledclowndoctors. D.Infactresearchdonebyscientistshasshownthatlaughterhasalotofhealthbenefits. E.Laughtermakestheworldabetterandmorecolorfulplace. F.Somepeoplemayfindtheideaembarrassingatfirst. G.Usinglaughtertherapyinchildren'shospitalshasproventobeinvaluable.
假设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处错误每句中最多有两处错误.错误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. Inordertoencouragetheseniorstotakeexerciseandrelaxthemwearegoingtoorganizeamountain﹣climbingactivityinApril10.Weweretogatherattheschoolgateandstartat720a.m.bybusandgetbackat700p.m.We'llclimbMangshanMountaininthemorningonwhichtopwe'llhaveapicnicatthenoon.Intheafternoonwe'llbedividedintogroupandhaveafreetime.Remembertakephotosandmakenotesforthephotoexhibitionortheessaycontesttobeheldlateatourschool.Besidestakingyourlunchanddrinkingwaterwithyou.UnlessyouwanttojoinpleasecometoStudents'UnionandsignupbeforeApril5.
Textingwhilecrossingthestreetwillsoon1baninHonoluluHawaii.FromOctober2youcouldbefinedifyoustepintoaHonolulustreetwhilelookingatyourphone.HonoluluisthefirstmajorU.S.citythatpassedalaw3saysNopedestrianshallcrossastreetorhighwaywhileviewingamobileelectronicdevice. Thelaw4includeallelectronicdeviceswithscreenscellphonestabletsgamingdevicesdigitalcamerasandlaptopcomputers.Thelawdoespermit5exception.Pedestriansmayusesuchdevicesinthestreettocallemergencyservicesandrescueworkerssuchasfirefightersandpolice6office. 7hopeitwilllowerthenumberofpeoplehitand8killbycarsinthecity.PedestriansdeathsinAmericahavebeencontinuouslyincreasingastheuseofcellphonesrises.Honoluluhas9muchpedestrianshitincrosswalksthanalmostanyothercityinAmerica.Thenumberofpedestriandeathsin201610riseto600011%higherthan2015.
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.错误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.每处错误及其修改仅限一词. 2.只允许修改10处多者从第11处起不计分. March5thisadayinhonorofLeiFengwhopeoplearecalledontohelpothers.OnthemorningofthatdaythisyearourclassmettheschoolgateandwenttoaHopePrimarySchoolbythebus.Uponarrivingtheretheygaveusawarmlywelcome.Wegavethestudentssomebooksfoodorclothes.Andthenweplayedseveralgamewiththemandtoldthemstories.Beforeweleavewetookaphotowiththem.Seetheirsmilingfaceswebothfeltasenseofhappiness.Wearrivedhomeandpromisedtogobackwheneverpossible.Howanunforgettableexperienceitwas!
OnNovember7LewisPughcompletedaone﹣kilometerswiminthefreezingwatersofKingEdwardCoveoffSouthGeorgiainAntarctica.Hewaswearingonlyhisswimmingglassescapandspeedos! Pughisanadvocateforouroceansandseasworkingtoprotecttheseecosystemwiththeirlargediversityofmarinelife.Whenaskedwhyhedoesn'twearawetsuitLewissaysIaskworldleaderstodoeverythingtheycantoprotectouroceans.Sometimesthestepstheyneedtotakearedifficultandunpopular.IfI'maskingthemtobecourageousImustalsobe.Swimminginawetsuitwouldnotsendtherightmessage. IttookPughabout19minutestocompletetheone﹣kilometerswiminAntarcticawherethewateraveragedabout1.6degreesCelsius.Hesaysthathisbodycanonlytolerateabout20minutesinthefreezingwatersbeforeitstartsshuttingdown.Asheswimshisbodytemperaturesteadilydropswhichinturncauseshismusclecontroltodropslowinghimdown.Whenheisdonewithhisswimhissupportteamrusheshimtoahotshowerandittakesalmostanhourforhisbodytemperaturetoreturntonormal. DoctorsandPughcautionthatonemustreceivemonthsoftrainingtoswiminsuchcoldwaters.Evenexpertswimmerswhoareunusedtofreezingwatercandrownwithinminutesbecauseofthephysicalshockexperiencedbythebody.Pughsayshetrainedforsixmonthsbeforethisswim. ThisisnotthefirsttimethatLewishasswumindangerousconditions.In2007heswamonekilometerintheNorthPoletodrawattentiontothemeltingArcticiceduetoclimatechange.In2015heswamintheBayofWhalesinAntarctica'sRossSeaaspartofhissuccessfulcampaigntohelpsetupamarinereservethere. 1WhydidLewisPughswimwithoutawetsuit? A.Toswimfaster. B.Toshowhisbravery. C.Tobuilduphisbody. D.Towinpublicattention. 2WhatdoestheunderlinedworditinParagraph3referto? A.Hisbody. B.Thewater. C.Hisbodytemperature. D.Thewatertemperature. 3What'sPugh'sadviceaboutswimminginfreezingwaters? A.Onemustbefullyprepared. B.Oneshouldbeexpertatswimming. C.Oneshouldbereadytotakeonchallenges. D.Onemustbeusedtolong﹣distanceswimming. 4Whatmaybethebesttitleforthetext? A.LewisPughswimmingforacause B.Howtosurviveaswimincoldwaters C.Howtoprepareforextremeswimming D.LewisPughachievingtheimpossible
1WhenyoutakeReadingintheDigitalAgeyouwill. A.walkintodifferentpeople'slife B.learnwaysofunderstandingtexts C.getbetteratcomputerskills D.shareopinionswithliteraryscholars 2WhowillhelpstudentsbetterunderstandthethemesofShakespeare'splays? A.Actors. B.Scholars. C.Historians. D.Videotutors. 3WhatcanpeoplelearnfromTheEuropeanDiscoveryofChina? A.China'sdiscoveryoftheWest. B.TheriseandfalloftheQingDynasty. C.TheimportanceoftheSilkRoad. D.China'sinterestinWesterntravellers. 4Whatarethesubjectsoftheseonlinecourses? A.Scienceandhistory. B.Mediaandhealth. C.Natureandenvironment. D.Languageandculture. 5Inwhichwaydothethreecourseshaveincommon? A.Theyareaimedatstudents. B.Theyareprovidedforfree. C.Eachlasts6weeks. D.Eachtakes2hoursperweek.
已知椭圆Ma＞b＞0的长轴长为6且经过点过点P并且倾斜角互补的两条直线l1l2与椭圆M的交点分别为BC点B在点C的左侧点E﹣70．Ⅰ求椭圆M的方程Ⅱ求证四边形PEBC为梯形．
设{an}是等比数列且a2a4＝a5a4＝27则{an}的通项公式为．
WhenHuangLizhitookherfirstclassinAfricansociologyattheUniversityoftheWitwatersrandinSouthAfricainFebruaryherprofessoraskedherandherclassmateswhatimpressesthemmostwhenitcomestoAfrica. UnexpectedlyHuang31foundthatwordslikepovertyandsafari﹣negativewordsthatwereoftenassociatedwiththecontinentinmediareports﹣werethekindoftermsherAfricanclassmatesdidn'twanttohear.InsteadtheypreferredtohearthequestionansweredinthiswayAfricaisthecradleofhumankindandAfricansarepassionateandgenerous. Apparentlytherearesomemisunderstandingsbetweenus.It'struethatwithincidentsliketheEbolaoutbreakinWesternAfricaandtheemergence出现ofpiratesoffthecoastofSomaliahittingthenewsit'seasyforustokeepforgettingthatAfricahasoneoftheworld'soldestcivilizations﹣Egyptbornbytheworld'slongestrivertheNile.TheproofisintheGreatPyramidofGizaandtheGreatSphinxofGizawhicharebothpopularamongtourists.AndthetombsofancientEgypthavealsobecomeendlesssourcesfortheliteratureandfilmindustries. WhenitcomestothenaturalenvironmentofAfricaourmisunderstandingsareonlybigger.Butthetruthisthatinsteadofbeingextremelyhotallyearandcoveredbydesertthecontinenthaslargeareasofsavannas稀树草原wherelionsgiraffesandzebraslivethesnowcappedKilimanjaro﹣thehighestmountaininAfrica﹣andeventhickforestontheislandofMadagascar.Thesemisunderstandingsareoneofthereasonswhythe2018BeijingSummitoftheForumonChina﹣AfricaCooperationwasheldonSept3and4﹣tounderstandeachotherbetter. IndeedonlybyvisitingAfricaherselfdidHuangseetheconvenientlivingconditionstheamazingnaturalbeautyandthefriendlypeople.InhereyesherclassmateswereashopefulaboutthefutureoftheirowncountriesastheywereaboutAfricaasawholeandtheywerequicktodemonstrateboththeirstrongwillandactivity.AtthatmomentIknewexactlywhattheywanted﹣theywantedtheirculturetoberespected. 1Whichofthefollowingbestexplainscradleunderlinedinparagraph2? A.Asmallbedforbabies. B.Abaskettoholdsomething. C.Aplaceforpeopletorelaxthemselves. D.Aplacewheresomethingimportantbegan. 2WhatcanweinferaboutAfricaaccordingtothepassage? A.Itisveryhotalltheyearround. B.It'snotasafecontinenttolivein C.It'sdifferentfromwhatweimagine. D.Itisboundtohaveabrightfuture 3WhichofthefollowingwouldHuangagreewith? A.Toseeistobelieve B.Thinktwicebeforeyoudo C.Amissisasgoodasamile D.Don'tjudgeapersonbyhisappearance 4Whatcanbeasuitabletitleforthetext? A.ValuingaCulture. B.UnderstandingAfrica. C.PayingaVisittoAfrica. D.DiscoveringaContinent.
Haveyoucomplained1yourfamilyyourbossorevenyourlife?Maybeeveryonehasbutafterreadingthisstoryyoumaychangeyourviewandtreattheworldwithanotherattitude. Anass驴2belongtoanherb﹣sellerwhogavehimtoolittlefoodandtoomuchworkcouldnotbearthelifeanylonger.SohemadearequesttoGodtobereleasedfromhispresentserviceandprovidedwith3master.Afterwarninghim4hewouldregretdoingitGodmadehimtobesoldtoatile﹣maker.Shortlyafterwardstheassfoundthathehad5heavyloadstocarryandharderworkinthebrick﹣fieldandaskedforanotherchangeagain.Godtellinghimthatitwouldbe6lasttimethathecouldsatisfyhisrequestmadehimsoldtoatanner皮革工.Theassfoundthathe7fallintoworsehands.Knowinghisnewmaster'soccupationhesaidItwouldhavebeenbetterformeeithertohavebeenstarvedbythefirstowner8tohavebeenoverworkedbythesecond.ButnowIhavealreadybeenboughtbymypresentowner9willpeeloffmyskinevenafterIamdeadandmakemeuseful. Wecanseethatpeoplewithdissatisfactioninaplacearenot10liketofindhappinessinanother.
Organic有机的farmingisatypeofagriculturethatbenefitsfromtherecyclinganduseofnaturalproducts.Useofdriedplantsnotonlysavesmoneybutalsoensuresthegrowthofcrops.Thetechniqueischaracterizedbytheuseofgreenmanure肥料biologicalpestcontrolmethodsandspecialfarmingtechniquestokeepsoilproductive.Limitingtheuseofman﹣madechemicalsorcompletelydoingawaywiththemreducestheriskofdiseases.Todayorganicfarmingisamajorandpreferredindustryaroundtheworld.Organicallygrownfoodproductshaveahugemarketwithfarmlandscoveringabout10%ofthetotalworld﹣farmlandcover.ThehardworkofSirAlbertHowardtheFatherofOrganicFarminghaspaidoff. AdvantagesofOrganicFarming 1Theeconomicsoforganicfarmingarecharacterizedbyincreasingprofitsthroughreducedwateruseandreducedsoilerosion侵蚀. 2Organicfarmingproducesthesamecropsasthoseproducedthroughtraditionalfarmingmethodsbutuseshalftheenergyandholds40%moretopsoil 3Farmingtheorganicwayenablesfarmerstogetridofweedswithouttheuseofanychemicals. 4Theuseofgreenpesticides杀虫剂isenvironmentallyfriendlyanddoesnoharmtohuman'shealth. DisadvantagesofOrganicFarming 1Organicmethodsoffarmingproducelesscomparedtotraditionalfarmingtechniques. 2Organicagriculturedoeslittletofightglobalclimatechange.ThoughorganicfarmingpracticesarerecognizedasgivingoutlessCO2butnottoasignificantdegree. Howeverthoughtherearesomedisadvantagesoforganicfarmingfarmswhereorganicmethodsforcroppinghavebeenusedhavemoreadvantagesthantraditionalfarms.Organicagricultureissurelybetterinthelongterm. 1TheunderlinedsentenceinParagraph1showsthatSirAlbertHoward. A.workedhardfornothing B.succeededinorganicfarming C.spentallhistimeonorganicfarming D.didn'texpectorganicfarmingtobesuccessful 2Accordingtothepassagecomparedtotraditionalfarmingorganicfarming. a.ismoreenvironmentallyfriendly b.producesalotmorefood c.useslessenergy d.resultsinmoreweedsinthefarmland e.isbetterforhuman'shealth A.abc B.acd C.ace D.bce 3Theauthor'sattitudetowardsorganicfarmingis. A.anxious B.hopeless C.unclear D.optimistic 4Thewriterwrotethispassagetotellus A.thedevelopmentofagriculture B.whatkindoffoodisbeinggrownatpresent C.whyorganicfarmingissopopulararoundtheworld D.whatorganicfarmingisanditsadvantagesanddisadvantages
目前你校有许多学生因为各种原因很少参加体育锻炼假定你是张华请你就此事向你校英语报写一封信倡导同学们积极参与体育锻炼. 内容包括 1.学生们不参加体育活动的原因 2.进行体育活动的好处. 注意 1.词数100左右 2.可以适当增加细节以使行文连贯 3.文章开头和结尾语已给出不计入总词数. Dearschoolmates Nowadaysmoststudentsdon'tdosportsforkindsofreasons.
设复数z满足1+iz＝2i则|z|＝
TimeTravel Ifyoucouldtravelintimewherewouldyougo?PerhapsyouwouldwatchanoriginalperformanceofaShakespeare'splayinElizabethanEngland?WhatabouthangingoutwithLaoziintheSpringandAutumnPeriod?Ormaybeyou'dvoyagefaraheadofthepresentdaytoseewhatthefutureholds. Thepossibilityoftimetravelisindeedappealing.Storiesexploringthesubjecthavebeenaroundforhundredsofyears.Perhapsthebestknownexampleissciencefictionnovel.TheTimeMachinewhichwaswrittenbyH.G.Wellsandpublishedin1895forthefirsttime.Itwasadaptedintoatleasttwofeaturefilmsofthesamenameaswellastwotelevisionversionsandalargenumberofcomicbookadaptations.Itisgenerallycreditedwiththepopularizationoftheconceptoftimetravelusingavehiclethatallowsanoperatortotravelpurposefullyandselectively.ThetermtimemachinecoinedbyWellsisnowuniversallyusedtorefertoavehicletransportingpeopleintothefarfuture. Butcouldtimetravelactuallybepossible?Somescientistssayyesintheory.Theyproposeusingcracksintimeandspacecalledwormholeswhichcouldbeusedasshortcutstootherperiods.Einstein'stheoryofrelativityallowstimetravelinextremecircumstances.AndBritishphysicistStephenHawkingsaysyoucouldtravelintothefuturewithareallyfastspaceshipgoingatnearlythespeedoflight.Thoughbuildingsuchaspaceshipwouldofcoursebenosimpletask. Evenifyoucouldtravelintothepastthereissomethingcalledthegrandfatherparadox.Itaskswhatwouldhappenifatimetravelerweretogobackintimeandhavehisowngrandfatherkilledforsomereasonandthereforepreventhimselffrombeingborn.Ifthetimetravelerwasn'tbornhowwouldhetravelbackintime? Andwouldyoureallyliketovisitthefuture?InH.G.Wells'bookthemaincharactertravelsintodistanttimewherehearrivesatabeachandisattackedbygiantcrabs.Hethenvoyages30millionyearsintothefuturewheretheonlylivingthingisablackobjectwithtentacles触角. Ifthat'swhat'sinstoremaybewearebetterjustlivinginthepresentdayafterall. 1ThenovelTheTimeMachinementionedinParagraph2aimstoshow. A.thecontributionofH.G.Wells B.thestory'sdifferentfeatures C.thelonghistoryoftimetravel D.people'sinterestintimemachine 2Einstein'sandHawking'stheories. A.suggestthepossibilitytoinventthetimemachine B.pushtheinventionofthefirstspaceship C.haveprovedwrongbysometimetravelers D.havesimilaritiesinmanyway 3InParagraph4grandfatherparadoxprobablyreferstotheideathat. A.thetravelerispreventedfrommeetinghisgrandfather B.thegrandfather'sdeathmakesthetraveler'sbirthimpossible C.thetravelergoesbackintimetoseekforhisgrandfather D.thereunionofthetravelerandhisgrandfatherbringshappiness 4Accordingtothepassagewhatisprobablytheauthor'sattitudetowardstimetravel? A.Skeptical. B.Unclear. C.Supportive. D.Unconcerned.
假定你是李华是你校音乐节的组织者之一.请你用英语给美国笔友Mike写一封邮件请他介绍一下他们学校的音乐活动并对你校音乐的组织提出建议. 注意1.词数100左右 2.可以适当增加细节以使行文连贯.
GreatholidaysinEurope! Doyoulikethebeachbutwantabitmore? ThencomeonanActiveBeachholidayatoneofourcentersinGreeceTurkeyorCroatia.Allthecentersarenearbeautifulbeachesandalloffersailingwindsurfingorwaterskiingwithourexcellentinstructors.Forachangefromthewateryoucanalsobookashorttriptoanearbyvillageandvisitthecolorfulmarketsoreatinalocalrestaurant.Attheendofthedayrelaxinyourhotelroomordancethenightawayatoneofouropen﹣airclubs. WhowasKingArthur?Wheredidhelive? Joinusonafive﹣dayUKRoadTripholiday.ImaginelifehundredsofyearsagoaswevisitancientStonehengeRomanBathandTintagelCastlethehomeofKingArthur.Learnthehistoryoftheseinterestingplacesfromyourguideasyoutravelinoneofourfamousbluecoaches.Intheeveningswestopatsomeofthebestyouthhostelsinthecountry.Theyhaveeverythingyouneedyoudontevenneedtopackasleepingbag! Areyouboredwiththeusualholidays?Doyouwanttodosomethingyoureallyenjoy? ThenFameCampisforyou!SpendaweekatHightreeHouseinYorkshireandlearnhowtoplaythepianoviolinandguitar!Bringyourtentandstayatacampsitenearthehouse.Attheendoftheweektryyournewskillsinaliveperformance. Howmanycountriescanyouseein21days? OnourExploreEuropeholidayyoucanseeten!Learnaboutthemfromourbestguidesasyouwatchthemgopastfromthewindowofanair﹣conditionedcoachandstayatsomeofEurope'stopcampsitesontheway.Ofcoursewe'llalsohavetimetodotheimportantthingssuchasvisitingtheEiffelTowerinParisthehistoricSistineChapelinVaticanandeatingappleѕtrudеlіnVіеnna. Formoreinformationaboutanyoftheseholidayscall08453334523orvisitwww.comewithusuk.com. 1TouristswhogoonanActiveBeachholiday. A.candosomewatersports B.cancookbythemselves C.willenjoyanopen﹣airconcert D.shouldbringtheirownsleepingbags 2IfyouwanttoknowmoreaboutTintagelCastlewhichholidayshouldyoutake? A.FameCamp. B.ActiveBeach. C.UKRoadTrip. D.ExploreEurope. 3WhatcanwelearnaboutExploreEurope? A.Itlasts10days. B.Itisacoachtour. C.Itisaself﹣guidedtour. D.Itgoespast21countries.
已知函数y＝sinωxω＞0在0上有最大值没有最小值则ω的取值范围为．
在平面直角坐标系xOy中过A44B40C04三点的圆被x轴截得的弦长为
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