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如图,圆C:x2﹣(1+a)x+y2﹣ay+a=0. (Ⅰ)若圆C与x轴相切,求圆C的方程; (Ⅱ)已知a>1,圆C与x轴相交于两点M,N(点M在点N的左侧).过点M任作一条直线与圆O:x2+y...
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高二上学期数学《》真题及答案
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﹣xy2x+y3+xx+y2的公因式是
设随机变量X与Y的概率分布分别为 且P{X2=Y2}=1 Ⅲ求X与Y的相关系数ρX
使用Line控件在窗体上画一条从00到600700的直线则其相应属性的值应是
X1=0,X2=600,Y1=0,Y2=700
Y1=0,Y2=600,X1=0,X2=700
X1=0,X2=0,Y1=600,Y2=700
Y1=0,Y2=0,X1=600,X2=700
某温度时浓度都为1mol·L-1的两种气体X2和Y2在密闭容器中反应生成气体Z.4s后X2Y2Z.的
X2+2Y2
2XY2
2X2+Y2
2X2Y
3X2+Y2
2X3Y
X2+3Y2
2XY3
先化简再求值已知2﹣3xy+x2﹣[2x2﹣35xy﹣2x2﹣xy]其中xy满足|x+2|+y﹣32
两个数xy在数轴上的位置如图所示请完成以下填空题.填>=或<.1x0y0.2﹣x0﹣y0.3x+y0
已知xy都是正实数且x+y-3xy+5=0.1求xy的最小值2求x+y的最小值.
理论上X2的取值范围为
-∞<X2<+∞
0≤X2≤+∞
X2≤1
-∞≤X2≤0
X2≥1
求使不等式成立的x的取值范围x﹣13﹣x﹣1x2﹣2x+3≥0.
设有微分方程x2lnxy-xy’+y=0.Ⅰ验证y1=x是微分方程的一个解Ⅱ利用变量代换y=xu化简
先化简再求值2xy﹣4xy﹣8x2y2+23xy﹣5x2y2其中xy满足x﹣12+|y+2|=0.
已知圆C1x2+y2+6x﹣4=0圆C2x2+y2+6y﹣28=0.1求过这两个圆交点的直线方程2求
先化简再求值2x2﹣3xy﹣5x﹣1﹣6﹣x2+xy﹣1其中xy满足x+22+|y﹣|=0.
同一条输电线三序电抗X1X2X0的大小关系是
X1>X2>X0
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设椭圆+=1a>0b>0的离心率e=右焦点F.c0方程ax2+bx-c=0的两个根分别为x1x2则点
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一元二次方程x2=2x的根是
x=2
x=0
x1=0, x2=2
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某温度时浓度都为1mol·L-1的两种气体X2和Y2在密闭容器中反应生成气体Z.4s后X2Y2Z.的
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2XY2
2X2+Y2
2X2Y
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2X3Y
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2XY3
若有以下程序#include<iostream>usingnamespacestd;classA{p
x1=10,x2=2
x1=12,x2=10
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.化简求值2﹣3x2y+xy﹣[2xy﹣4xy﹣x2y+x2y]其中xy满足|x﹣3|+y+2=0.
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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
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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
设x为实数则“x<0”是“”的
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
以棱长为1的正方体各面的中心为顶点构成一个正八面体再以这个正八面体各面的中心为顶点构成一个小正方体那么该小正方体的棱长为
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.
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.
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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