山西省懷仁一中2025屆高考考前模擬英語試題考生須知：1．全卷分選擇題和非選擇題兩部分，全部在答題紙上作答。選擇題必須用2B鉛筆填涂；非選擇題的答案必須用黑色字跡的鋼筆或答字筆寫在“答題紙”相應(yīng)位置上。2．請用黑色字跡的鋼筆或答字筆在“答題紙”上先填寫姓名和準(zhǔn)考證號。3．保持卡面清潔，不要折疊，不要弄破、弄皺，在草稿紙、試題卷上答題無效。第一部分（共20小題，每小題1.5分，滿分30分）1．Sincemanyformerdrugabusershavepsychologicalproblems,theyoftenneedsupportgroups_________theycantalkabouttheirstrugglesandfindnewwaystomanageintheworld.A．which B．whatC．where D．when2．ThebeautifulmountainvillagewespentourholidaylastyearislocatedinisnowpartofGuangxi.A．which;where B．where;what C．that;what D．when;which3．High-speedtrainswhichtravelthroughmyhometown________upto250kmperhourmakeitasmallworld.A．with B．a(chǎn)gainstC．a(chǎn)t D．over4．______flag-raisingceremonywasheldattheGoldenBauhiniaSquareonJuly1tocelebrate______17thanniversaryofHongKong’sreturntoChina.A．A;/ B．A;theC．The;the D．/;the5．Alongwiththeemailwasmybrother’spromise______Icamefirstinthecompetition,hewouldbuymeanMP4.A．what B．that C．thatif D．whether6．Notfarfromtheclubwasthereagarden,_____ownerseatedinitplayingbridgewithhischildreneveryafternoon.A．whose B．itsC．which D．that7．—HowcanIwakeupsoearly?—Setthealarmat5:00am.,youwillmakeit.A．a(chǎn)nd B．butC．or D．so8．________whoareabletoworkthroughthestrugglearethe________whoaregoingtobesuccessful.A．Someone;one B．Anyone;oneC．He;ones D．Those;ones9．Nostudent________gooutofschooltohavelunchwithoutpermissionoftheheadteacher.A．might B．mustC．shall D．could10．Theconditionsinthelocalschoolwerefairly_____,noelectricityandnobasicteachingfacilitiesavailable.A．unique B．typicalC．Primitive D．Stable11．—Helen,areyougoingIotheairporttopickupJackthedayaftertomorrow?—________tomorrownight.Iwouldgo.A．Werehetocomeback B．IfhewasabouttocomebackC．Hadhecomeback D．Ifhewouldcomeback12．Intheearlymorningallofusstoodatthetopofthemountain___________eastofthecity,watching__________burningsunrising.A．/;a B．the;aC．the;the D．/;the13．IwastellingajokeandSamjustinterruptedmetotelladifferentone.Healways_____!A．biteshistongueB．saveshisskinC．stealsmythunderD．pullsmyleg14．Theyintendedtohavetheschoolbetterequipped，thelocalgovernmentwas notabletogetenoughmoneytodoso.A．unless B．while C．a(chǎn)lthough D．once15．Thefolksweredelightedatthemessageoftheirrelatives_______thatmineexplosion.A．survived B．tosurvive C．weresurviving D．surviving16．BythetimeIsawtheangryexpressiononhisface,I________exactlywhatIwashavingtoface.A．knewB．hadknownC．wouldknowD．haveknown17．Wheneveryou________apresent,youshouldthinkaboutitfromthereceiver’spointofview.A．bought B．havebought C．willbuy D．buy18．____________youarefamiliarwiththeauthor’sideas,tryreadingallthesectionsasquicklyasyoupossiblecan.A．NowthatB．EversinceC．SothatD．Incase19．Therearevariousthingsonsale,soyoucanchoose______interestsyou.A．whoever B．nomatterwhoC．whatever D．nomatterwhat20．—BoB．couldIuseyourcomputerthisevening?—Sorry.Iareportonitthen.A．willbewriting B．havebeenwritingC．havewritten D．willhavewritten第二部分閱讀理解（滿分40分）閱讀下列短文，從每題所給的A、B、C、D四個選項(xiàng)中，選出最佳選項(xiàng)。21．（6分）Manyyearsago,peoplereliedonthesun,themoonandstarstofindtheirwayaround.Later,thecompasswasintroduced.Andnow,wehavesatnav（衛(wèi)星導(dǎo)航）systemstoguideus.Asatnavsystemusesgroupsofsatellitestoshowtheuser’slocation.Theysendinformationtoareceiver,suchasasmartphone,toshowuswhereweare.TheearliestbuiltsatnavsystemistheGlobalPositioningSatelliteSystem,whichbelongstotheUS.ThenthereisRussia’sGlobalNavigationSatellitesystem，theEuropeanUnion’sGalileoandChina’sownsatellitenavigationsystem,Beidou.OnOctober18,2017,anARJ21-700plane,whichwasthefirstdomestically（國內(nèi)地）producedjetequippedwiththeBeidounavigationsystem,successfullycompletedatestflight.TheresultsshowedtheperformanceofthesystemdevelopedbyChinamatchesthatofsimilarsystemsproducedabroad,accordingtotheCommercialAircraftCorporationofChina.Sinceitsintroductionin2000,theBeidounavigationsystemhasbeenincreasingnumbersofapplicationslinkedtoeverydaylife,fromsharedbikestofarming.Whenitcomestosharedbikes,smartlocksthatsupportBeidouchipsoffermoreaccuratepositioningthanothers,makingiteasiertofindabike.FarmerscanuseBeidou-enabledtractorstoplow（犁）thesoilanduseunmannedaircraftwithBeidoutosowseeds,whichcanimproveefficiencyandmakebetteruseofresources.Beidou’sfarmingapplicationshavespreadfromHeilongjiangProvincetoBeijing,Liaoning,Shanxi,HubeiandotherregionsacrossChina.Withitsmanyuses,theBeidounavigationsystemisevenplayingabigroleintheBeltandRoadInitiative（一帶一路）.“Todate,theBeidousystemhascoveredmostpartsoftheAsia-Pacificregion,aswellascountriesalongtheSilkRoadEconomicBeltandthe21stCenturyMaritimeSilkRoad,”saidYangChangfeng,chiefdesigneroftheBeidousystem.Today,therearemorethan20Beidousatellitesaboveourheads,andChinaplanstolaunchevenmorethisyeartoexpandtheBeidounetworktobetterservetheBeltandRoadInitiative.“AsBeidouexpandsitsoverseasreach,itwillbeincreasinglypopularinthelogistics（物流）industry,”saidMiaoQianjun,SecretaryGeneralofthenavigationservicesassociation.“Ships,forexample,canuseittopositionthemselveswhilesailingacrossoceanstoEuropeancountries,nolongerlimitedtoSoutheastAsianregionsinthenearfuture.1、Whatisthepurposeofthefirsttwoparagraphs?A．Tocomparesomemodernsatnavsystems.B．Todescribethebenefitsofsatnavsystems.C．Totellushowsatnavsystemswerecreated.D．Tointroducesomesatnavsystemsandtheirfunctions.2、WhatcanweknowabouttheBeidounavigationsystemaccordingtothearticle?A．Itwasusedsuccessfullyinanewjetplane.B．Itismorepowerfulthanothersatnavsystems.C．ItwasintroducedtoChinaonOctober,2017.D．Itwasn’tusedinoureverydaylifeuntilrecently.3、Accordingtothearticle,theBeidounavigationsystemisalreadywidelyusedfor_______.A．plowingthesoilandsowingseedsB．improvingtheefficiencyofnetworkC．producingmoresmartlocksforsharedbikesD．navigatingshipsacrossoceanstoEuropeancountries4、WhatisMiaoQianjun’sattitudetowardthefutureoftheBeidousystem?A．Worried.B．Casual.C．Positive.D．Doubtful.22．（8分）Lastweek,twocompanies,KittyHawkandUber,announcedtheirplanstobringflyingcarstorealityverysoon.KittyHawkpresident,SebastianThrun,announcedKittyHawk’sflyingcarplanslastMonday.Accordingtoitswebsite,thecariselectric-poweredandwillbeabletotravelatspeedsupto40kilometersanhour.Itsayssuchamachine“doesnotrequireregistrationorapilot’slicenseandmaybeflowninuncrowdedareasforrecreationalpurposes.”Asofnow,thecarcanonlybeflownoverfreshwater.KittyHawkismakingalistofpeopleinterestedinbuyingtheflyingcar.Theymustpayadepositof$100.Thosewhogettheirnamesonthelistearlywillreceive$2,000offthefinalcostofthecar.However,KittyHawkhasnotyetannouncedtheprice.Itsfirstflyingcarsareexpectedtogoonsalebytheendofthisyear.UnliketheKittyHawkcompany,Uberdoesnotplantobuilditsflyingcars.UberexpectstolaunchflyingtaxisinDallas-Ft.Worth,Texas,USby2020.LiketheKittyHawkcar,Uberflyingtaxiswilluseelectricpower.Ubersaysitsflyingtaxiscouldtravelupto241kilometersanhour.ThecompanysaysthatcouldreducethetraveltimebetweenSanFranciscoandSanJose,Californiafrom2hoursontheroadto15minutesintheair.RiderscouldusetheUberapptobookaflyingtaxitotakethemtotheirdestinations.Thecompanyhasnotyetsaidhowcostlyairtaxitravelwouldbecomparedtoroadtaxitravel.Soonerthanyouthink,flyingcarsmayappearinthesky.Muchconvenienceastheywillbring,justimaginehavingtoavoidotherflyingcars.Also,whatifyourbatterydieswhenyouareintheair?And,howwillyouknowwheretoland?1、WhatmayKittyHawk’sflyingcarbeusedforatpresent?A．Acceleratingthespeed.B．Havingfun.C．Advertisingthecompany.D．Fetchingwater.2、WhatdoweknowaboutKittyHawk’sflyingcarfromthethirdparagraph?A．Itcoststwothousanddollarseach.B．Itcantraveloverwater.C．Itoffers$100toitspotentialbuyers.D．Ithasn’tgonetomarket.3、InwhatwayisUber’sflyingtaxisimilartoKittyHawk’sflyingcar?A．Theytravelatthesamespeed.B．Theyareelectric-powered.C．TheyaresupportedbytheUberapp.D．Theyrequireaflyinglicense.4、Whatisthepurposeofthelastparagraphofthetext?A．Tocallforpublicdonations.B．Tointroducesomeadvantages.C．Topromoteinterestinscience.D．Totalkaboutpossibleproblems.23．（8分）Thompson’sChildrenAshersonCameronsitsathislaptopcompletingataskforhismathdegreecourse.AlisonThompson,afull-timemumisbusyhelpingherdaughterEmma(twoyearsyoungerthanCameron)getdressed.WhilehelphasalwaysbeenavailableforEmma,AlisonandherhusbandalsohavetofighttogetCameronthesupportheneeds."PeoplecouldseethatEmmahasspecialneedsbutbecauseCameronwasdoingsowellatschool,histeachersneverthoughttherewasaproblemwithhim,“saysAlison.IttookAlisonandherhusbandawhiletorealizetheirsonwasdifferent.Cameron'sabilitydidn’tbecomeclearuntilhebeganprimaryschool.Onceheevencorrectedtheteacherwhenshetoldtheclassthatzerowasthelowestnumber.Camerontoldhershewaswrongbecausetherewerenegativenumbers(負(fù)數(shù)).Hewasfouratthetime.Now14-year-oldCameronisatsecondaryschool,studyingforadistancelearningmathdegreewiththeOpenUniversity,havingsailedthroughhisGCSEat11andhisA-levelat12,achievingtopgrades.Bethany,anotherdaughterofAlison,isbrighttoobutnotgifted.Sheistheonewhowillremindabsent-mindedCamerontoputonhiscoat.Shealsohelpshimoutinsocialsituations.Emmaattendsaspecialistschoolandthefamilyisquicktocelebratehersuccessestoo.“Theotherdayshedidupthebuttonsonhercoat,whichwasrealprogress,”Alisonsays.LatelastyeartheThompsonstookpartinatelevisiondocumentary(紀(jì)錄片)toprovethatnotallgiftedchildrenaretheresultofextremelyambitiousparents.Giftedchildrenneedsupporttoo,buttheirlivesdon'thavetobethatdifferent.Cameronisanexample1、Whatdoesparagraph1indicate?A．CameronhelpsEmmawithhermathtasks.B．TeachersatschoolignoredEmma'sproblems.C．BothCameronandEmmaneedparentalsupport.D．ThecoupleoftenhavefightsbecauseofCameron.2、Thereareatleast__________peopleinMrs.Thompson’sfamily.A．threeB．fourC．fiveD．six3、Whatcanbeknownfromthepassage?A．Emmahaslearnedtotakegoodcareofherself.B．Cameronshowedhisgiftbeforeprimaryschool.C．Thechildrenofthefamilyarebrightandgifted.D．Giftedkidsarenotsodifferentaspeopleexpect.24．（8分）Theworld’spopulationisprojectedtoreach11billionbytheendofthecentury.Feedingthatmanypeoplewillbeachallenge,anditisfurthercomplicatedbytheimpactofclimatechangeonagriculture.Thatiswhysomepeopleadvocateanunusualwaytoboostthefoodsupplyandfeedpeoplesustainablybyeatinglessmeatandmoreinsects.About2billionpeoplealreadyeatbugs.Mexicansenjoychilly-toastedgrasshoppers.Thaistuckintocricketstir-friesandGhanaianssnackontermites.InsectsareslowlycreepingontoWesternmenusasnoveltyitems,butmostpeopleremainsqucamish(拘謹(jǐn)).Yettherearethreereasonswhyeatinginsectsmakessense.First,theyarehealthierthanmeat.Therearenearly2000kindsofedibleinsects,manyofthempackedwithprotein,calcium,fiber,ironandzinc.Asmallservingofgrasshopperscancontainaboutthesameamountofproteinasasimilarsizedservingofbeef,buthasfarlessfatandfarfewercalories.Second,raisinginsectsischeap,orfree.Littletechnologyorinvestmentisneededtoproducethem.Harvestinginsectscouldprovidelivelihoodstosomeoftheworld’spoorestpeople.Finally,insectsareafarmoresustainablesourceoffoodthanlivestock.Livestockproductionaccountsfornearlyafifthofallgreenhouse-gasemissions,that’smorethantransport.Bycontrast,insectsproducerelativelyfewgreenhousegasesandraisingthemrequiresmuchlesslandandwater.Andtheyeatalmostanything.Despiteallthis,mostWesternersfindinsectshardtoswallow.Onesolutionistouseproteinextractedfrombugsinotherproductssuchasreadymealsandpastasauces.Nothavingtolookatthebugsandemphasizingtheenvironmentalbenefitsmightmaketheideaofeatinginsectsabitmorepalatable.1、Whatisthedirectreasonwhysomepeopleadvocateeatinginsects?A．InsufficientfoodsupplyB．ClimatechangeC．TherapidincreaseofpopulationD．Insects’highnutrition2、Fromthepassage,wecaninferthat.A．eatinginsectsishealthierthaneatingbeefB．eatinginsectsispopularamongwesternersC．eatinginsectscanhelppeopleloseweightD．eatinginsectscauseslessdamagetotheenvironment3、Howcanwemakeitmoreacceptabletoeatinsects?A．ByclosingyoureyeswheneatinginsectsB．ByeatinginsectstogetherwithotherfoodC．Byputtinginsects’nutrientsintootherfoodproductsD．Byconsideringtheenvironmentalbenefitsofeatinginsects25．（10分）TheRoboticIndustriesAssociation(RIA)announcedthatCatherineMorris,groupleaderanddirectorofautomotivesalesatATIIndustrialAutomationandDr.HowieChoset,roboticsprofessoratCarnegieMellonUniversityandco-founderoftheAdvancedRoboticsforManufacturing(ARM)Institute,havewonthe2019EngelbergerRoboticsAward.TheywerehonoredataspecialdinneronApril10duringtheAutomateShowandConferenceMorris,whobecomesjustthefourthwomantowintheawardishonoredinthecategoryofleadership.Shesaid,“Iamverysurprisedandextremelyhonoredtobethisyearswinneroftheaward.Besides,Icannothelpbutfeelgrateful.”JeffBurnstein,RIApresidentsays,“IcanthinkofveryfewpeopleinthehistoryoftheroboticsindustryascommittedtothegrowthofourindustryasCatherine.Infact,overthepasttwodecades,she’sfoundtimetoholdalmosteverykeypositioninourtradegroup,fromMembershipCommitteeChair,toAutomateShowCommitteeChair,tooverallChairofRIA,beingthefirstandonlywomantoholdthatroletodate.”Dr.ChosethasreceivedtheawardforEducation,becomingthethirdpersonfromCMUtowintheaward.Chosetisbestknownforbuildingsnake-likerobots.Heandhisresearchteamhavestudiedhowtheserobots,withtheiruniqueabilitytomovethroughdifficultenvironments,canbeusedforsearchandrescue,formappingandinspectingcaves,pipesandotherlimitedspaces,andformanufacturing,saidMartialHebert,directorofCMUSRoboticsInstitute.Dr.Chosetisaninnovativeeducator,Hebertadded,whoisdevotedhimselftoteachinghisstudents.HisFDA-approvedsurgicalsnakerobotshavebeenappliedinsurgeryintheU.S.andEuropesince2015.Besides,consideringhisrolesasaco-founderoftheARMInstituteandasafoundingeditorofthejournalScienceRobotics,youseethatDrChosetiswelldeservingofourindustry’shighesthonor1、Morrishasreceivedthe2019EngelbergerRoboticsAwardduetoherA．marketingconcepts B．excellentleadershipC．teachingskills D．uniquecreativity2、WhatcanwelearnfromJeffBurnsteinaboutMorris?A．Sheisthefirstwomentowintheroboticsaward.B．ShehasmademorepeoplecommittedtotheroboticsindustryC．ShehastheexperienceofholdingdifferentimportantpostsD．SheistheonlywomantoholdMembershipCommitteeChair3、Whyaresnake-likerobotsmentionedinParagraph3?A．TopraiseChoset'scooperationabilityB．ToshowChoset'soutstandingcontributionC．ToadvertiseaneffectiveproductforurbansearchD．Toprovetherapiddevelopmentofmoderntechnology4、WecanlearnthatDr.Choset'ssnakerobotshaveplayedaroleinA．helpingdoctorsoperateonpatientsB．replacingworkersinafactoryC．helpingstudentsdoexperimentsinalabD．warningworkersofsomethingdangerous5、Whichofthefollowingwouldbethebesttitleforthistext?A．EngelbergerRoboticsAwardandthewinnersB．EngelbergerRoboticsAwardandtheirimportanceC．TheRIAannouncedEngelbergerRoboticsAwardD．ChosetandMorriswonEngelbergerRoboticsAward第三部分語言知識運(yùn)用（共兩節(jié)）第一節(jié)（每小題1.5分，滿分30分）閱讀下面短文，從短文后各題所給的A、B、C和D四個選項(xiàng)中，選出可以填入空白處的最佳選項(xiàng)．26．（30分）Asachild,Iwasalwaystoldto“eatmygreens”.Theseweretheunappealingvegetablesthatsatontheedgeofmyplate.Peas,andgreenbeans,alllookedandtasted1.Let’sfaceit,whenthereweresomanyotherdelicioustreatsto2,whyeatboringvegetables?Sincethenmytastebudshave3andI’malsofullyawareofthehealthbenefitsofeatingfreshvegetables.Butwestillneed4oftheamazinggoodnessthesegreensuperfoodsgiveus.IntheUK,acampaignhasbeen5forseveralyearstoencourageustoeatour“5ADay”—fiveportionsoffruitandvegetables.That’s6evidencehasshowntherearesignificanthealth7togettingatleastfive80gportionsofavarietyoffruitandvegetableseveryday.ButIstruggletryingtofitthesefiveportionsintomydaily8,partlybecauseIhaveasweet9andvegetablesare,well,tasteless.Researchershavebeen10howtomakeeatingvegetablesmore11.Theyanalysedthepsychologybehindourfood12andfoundthatmostofusare13bytaste.BradTurnwaldfromStanfordUniversitysaysthat“studiesshowthatpeople14tothinkofhealthieroptionsaslesstastyforsomereason.”InEurope,aprojectcalledVeggieEAThasalsobeentryingtofindwaystogetpeopleto15morevegetables.Projectleader,ProfessorHeatherHartwellbelievesin16encouragingpeopleintoeatingtherightthings.Oneideahasbeentoputa17ofatastylookingfruitonasupermarkettrolleyasa18aboutbuyingsomethingfromthefruitstore.Shesays,“Choiceisareally19thing.Butmakingvegetableslookattractivewillincreasetheirsales.”Certainly,eating“twistedcitrus-glazedcarrots”doessoundtempting,evenifitjust20likeacarrot,butifitmakesuseatmorevegetablesthenthatcanonlybeagoodthingforourhealth.1、A．deliciousB．disgustingC．ripenD．sweet2、A．buyB．prepareC．enjoyD．offer3、A．developedB．a(chǎn)ppearedC．existedD．shrank4、A．talkingB．informingC．remindingD．warning5、A．planningB．runningC．a(chǎn)imingD．intending6、A．whyB．howC．whenD．because7、A．needsB．issuesC．benefitsD．risks8、A．dietB．educationC．workD．exercise9、A．tendencyB．toothC．preferenceD．a(chǎn)ppetite10、A．showingB．discoveringC．reportingD．studying11、A．a(chǎn)ttractiveB．a(chǎn)ppropriateC．beneficialD．independent12、A．wastesB．valuesC．choicesD．judgments13、A．confusedB．disturbedC．challengedD．motivated14、A．manageB．tendC．a(chǎn)greeD．decide15、A．growB．harvestC．storeD．eat16、A．suddenlyB．slowlyC．firmlyD．seriously17、A．pictureB．lotC．varietyD．number18、A．signB．concernC．hintD．clue19、A．complexB．easyC．quickD．casual20、A．looksB．smellsC．feelsD．tastes第二節(jié)（每小題1.5分，滿分15分）閱讀下面材料，在空白處填入1個適當(dāng)?shù)膯卧~或括號內(nèi)單詞的正確形式。27．（15分）Manyathleteshavebeentoldthatsmilingwhile1．(sweat)willmakeoureffortsfeeleasier.Amarathonrunnersmiledwidelythroughthefinalmilesofhisfastest-evermarathon；afterward,hesaidwhathehadhoped2．(be)thatthesmilingwouldeasehimtothefinishline；Buttherehasbeenlittlesolidscientificevidencetosupportthisidea.Inrecentyearsseveralpaststudies3．(examine)whetherdeliberatelysmilingcanmakechangestohowpeoplefeelpsychologicallyduringraces,4．fewhavelookedatthephysicaleffect5．sportsperformance.Researchersdecided6．(gather)agroupofexperiencedrecreationalrunnersandhavethemalternativelysmilebroadlyastheyran.Manyoftherunnersfounditdifficulttosmilethroughoutthewholesession,though.Theirsmilesbecame7．(increase)fixedandunnatural.Suchfalsesmilesmake8．(few)facialmuscles(肌肉)startworkingthanthesincereversionandmostlikelyresultinless9．(relax)andperformanceimprovement.Sothekeytousingahappysmiletomakeyou10．betterrunnermaybetosmilesincerelyandoftenneararace’send,butin30-secondbursts,ratherthanconstantly.第四部分寫作（共兩節(jié)）第一節(jié)短文改錯（滿分10分）28．（10分）閱讀下面短文，并根據(jù)短文后的要求答題。文章共有10處錯誤，每句中最多有兩處。錯誤涉及一個單詞的增加，刪除或修改。增加：在缺詞處加一個漏詞符號(∧)，并在此符號下面寫出該加的詞刪除：把多余的詞用斜線劃掉（/）修改：在錯誤的詞下面畫一橫線（_______）,并在該詞下面寫出修改的詞注意：1、每處錯誤及其修改均僅限一詞2、只允許修改10處，多者（從第11處起）不計(jì)分。3、必須按答題要求做題，否則不給分。Weweredrivingintherightlanewhile,allofsudden,ablackcarjumpedoutofaparkingspacerightinfrontofus、Mytaxidriverslammedonmybrakes,skidded、andmissedtheothercar’sbackendthroughjustinches!Thedriveroftheothercar,theguywhoalmostcausedabigaccident,turnedhisheadangrilyandstartedyellingbadwordatus、Mytaxidriverjustsmiledandwavedattheguy、Imean,hewasfriendly、SoIsaid,“Whydoyoujustdothat?Thisguyalmostruinedyourcarandsentustohospital!”Andthiswasthatmytaxidrivertoldme,whichIcall“TheLawoftheGarbageTruck”、Manypeopleareasgarbagetrucksandtheyrunaroundfullofgarbage,fulloffrustration,fullofanger,andfullofdisappointment、Theirgarbagepilesup,theyneedaplacetodump（傾倒）it、Andifyouletthem