喀什市20252026學(xué)年第一學(xué)期高一期中測試卷英語時間：120分鐘滿分：150分第一部分聽力(共兩節(jié)，滿分30分)注意，聽力部分答題時請先將答案標(biāo)在試卷上，聽力部分結(jié)束前你將有兩分鐘的時間將答案轉(zhuǎn)涂到答題卡上。第一節(jié)(共5小題;每小題1.5分，滿分7.5分)聽下面5段對話。每段對話后有一個小題，從題中所給的A、B、C三個選項中選出最佳選項，并標(biāo)在試卷的相應(yīng)位置。聽完每段對話后，你都有10秒鐘的時間來回答有關(guān)小題和閱讀下一小題。每段對話僅讀一遍。1.WhatgiftdidthemansendtoAlicelastyear?A.AB.AC.Aofearrings.B.Acellphone.C.Abag.2.Wherecanwefindthewomanthisafternoon?A.Atthehospital.B.InC.Inhop.C.Inheroffice.3.Whatwillthewomandoafterwork?A.HaveB.GoC.Packeefdinner.B.GototheJungleCafé.C.Packupforthetriphome.4.Wheredoesthewomanefrom?A.America.B.Australia.B.Australia.C.Canada.5.Howmuchshouldthewomanpay?A.$220.B.$90.C.$180.第二節(jié)(共15小題;每小題1.5分，滿分22.5分)聽下面5段對話或獨白。每段對話或獨白后有2至4個小題，從題中所給的A、B、C三個選項中選出最佳選項，并標(biāo)在試卷的相應(yīng)位置。聽每段對話或獨白前，你將有5秒鐘的時間閱讀各個小題;聽完后，各小題將給出5秒鐘的作答時間。每段對話或獨白讀兩遍。聽下面一段對話，回答第6和第7題。6.What’sthewoman’sfavoritesporttowatch?A.Baseball.B.Basketball.C.Football.7.Whatcanweknowabouttheman?A.Helikeswatchingandplayingsports.B.Hetakessportsnearlyeveryday.C.Hedoesn’tlikeplayingsports.聽下面一段對話，回答第8至第10題。8.Whatkindofrestaurantdoesthemanremend?A.AnItalianrestaurant.B.AGreekrestaurant.C.ATurkishrestaurant.9.Whatisthesaladmadeofintherestaurant?A.Vegetablesandoliveoil.B.Vegetablesandcheese.C.Meatandcheese.10.Whatdoesthewomanlikefordessert?A.Sweets.B.Cakes.C.Cheese.聽下面一段對話，回答第11至第13題。11.Whatdoesthewomanthinkofthebedroom?A.Bright.B.New.C.Small.12.Whatdoesthewomanlikebest?A.Thekitchen.B.Theview.C.Thelivingroom.13.Whatwillthespeakersdomostprobably?A.Havetheshowerrepaired.B.Buysomefurniture.C.Keepsearching.聽下面一段對話，回答第14至第17題。14.Whatdoesthemando?A.Apoliceman.B.Afirefighter.C.Areporter.15.Howmanykidsdiedfromthefire?A.2.B.5.C.28.16Wheredidtheboythrowthecigaretteend?A.Onthecarpet.B.Onthesofa.C.Onthetable.17.Whywastheboyabletotouchthecigaretteend?A.Hisfatheraskedhimtothrowit.B.Hisfatherwasdrunkandsleeping.C.Hisfatherlefthimaloneathome.聽下面一段獨白，回答第18至第20題。18.Howcanfrozenfoodbekeptcoldatordinarytemperatures?A.Byusingbags.B.Byusingwater.C.Byusingpaper.19.Whatisadvisedtodowhencamping?A.Usespecialdryfoods.B.Nevercookmeatoreggs.C.Keepmilkinacoolerbox.20.Whatisthepassagemainlyabout?A.Howtopickupfreshfood.B.Howtoeathealthilyindifferentweather.C.Howtokeepfoodfromgoingbadinsummer.第二部分閱讀理解(共兩節(jié),滿分50分)第一節(jié)(共15小題;每小題2.5分,滿分37.5分)閱讀下列短文，從每題所給的A、B、C、D四個選項中選出最佳選項，并在答題卡上將該選項涂黑。AEightfitnessexercisesyoucandoathomeWalkingAneffectivewalkingworkoutathomewillhelptostrengthenyourlegs,whilegettingsomelowimpactaerobicexerciseaswell.Ifyoudon’thaveanystairsavailable,justwalkaroundthehouseafewtimes—itmaynotbeveryexciting,butitwilldothejob!JumpingjacksThesearealwaysfun,astheybringbackmemoriesofbeingakid!Whohasn’tdonejumpingjacksforfunasachild?Well,surprise—theyarealsogreatcardioexercises,andgoodforwarmingup,too.PushupsTheseareprobablynotthemostfavoriteexerciseofmanypeople,butwhiletheycanbehardtodo,youcanfindeasierwaystodothem.Youdon’tneedtopretendyou’re“Rocky”,anddothemwithonehand:justdowhatworksforyou.Dothemonyourknees,insteadofkeepingyourlegsstraight.Or,dothembystandingupagainstawall.Youwillbuilduparmstrengthandworkoutmusclesinyourchestarea.LegliftsThesearegreatforbuildingupstrengthandmusclesinyourlegs.Ifyoufindithardtodotheexerciseswithyourlegsstraight,trybendingthemslightly.CrunchesIt’sthebestexerciseforbuildingupandstrengtheningbellymuscles.Whenyou’rejustgettingstarted,don’tworryaboutgettingyourheadallthewayup.Solongasyou’regoingupuntilyoufeelthestretchingofthemuscles,youwillseesomebenefit.JogginginplaceJoggingisagreatexerciseforyourheart.YoucanjoginplaceathomewhilewatchingTVorlisteningtomusic.Theonlyequipmentyouwillrequireisagoodpairofshoes,toeliminateanystresstoyourlegs.SquatsThesearewonderfulexercisesforyourlegsandbottoms.Youcanevenjusttrythesebysittingandstandingupagainfromaregularchair,ifyou’refindingthemtobetoodifficult.Aslongasyou’reabletodoafewrepetitions,youwillprovidesomebenefittoyourbody.DancingDancingisawonderfulexercise,whichisgreatforyourheart.Notonlythat,butitcanliftyourspiritsaswell,andgiveyouroverallfeelingaboost.1.Whichcolumndoesthisarticlebelongtoifinthenewspaper?A.Health. B.Entertainment. C.Travel. D.Advertisement.2.IfTomwantstostrengthenhischestmuscle,whichexerciseismostsuitableforhim?A.Walking. B.Pushups. C.Jumpingjacks. D.Squats.3.Whatexercisesarebestforheart?A.WalkingandPushups. B.LegliftsandCrunches.C.SquatsandDancing. D.DancingandJogginginplace.【答案】1.A2.B3.DBIcanstillrememberthefirstdaywhenImetmybestfriend.Shehadjustmovedtotheneighborhoodandhergrandmotherbroughtherdowntomeetme.Ihidbehindmymotherandshehidbehindhergrandmother,scaredoflookingateachother.Soon,welosttheshynessandstartedplayingwitheachother,ridingbikestoeachother’shouseandhavingsleepovers.In7thgradeshewasgoingthroughfamilyproblems.However,everysummerwewouldsitateachother’shouse,watchmoviesonTVandtalkaboutalltheboysweliked.ItwaslastyearthatInoticedtheproblem.Shesufferedfromclinicaldepression(臨床抑郁癥),andhadtogotoahospitalduringtheday.Iwasverysorryforheratfirst.Butwiththelatenightcallsandmeetingeachotherhalfwayupthestreetatmidnight,westillstayedintouch.Iwantedtobethereforhersincehernewbestfriendlefther,andIknewIstillcaredaboutherlikeasister.Yesterdayshecametomeandsaid,“Ineverknewwhatabestfriendwasuntilyouweretheonlypersonthatwouldstopmefromcuttingmyselfandthatevermademefeelbetteraboutmyselfandmyproblems.Youdidn’tknowthisbutIwastryingtokillmyselfthatverynightyoucalledmeandIwascrying.Ioweyousomuch,andyoudidn’tevenknowyouwerehelpingme.”Webothcried.AndIguessakindoflessonfrommylifesofaristonevergiveupyourfriends.Eveniftheyaren’tascoolasothers,orpeoplethinktheyarecrazy,theyneedsomeonethere.Ifyouleavethem,youwillonlybeverysorry.Soifyourfriendsneedyou,andyoucareaboutthem,youshouldbealwaysthereforthem.4.Whydidthetwogirlshidebehindtheirfamilymemberswhentheyfirstmet?A.Becausetheywereplayingagame. B.Becausetheydidn’tlikeeachother.C.Becausetheyquarreledbefore. D.Becausetheywerebothshy.5.What’stheproblemofmybestfriend?A.familyproblems B.havingdifficultyinstudyingC.clinicaldepression D.badrelationshipwithclassmates6.Whatwouldhavehappenedtoherfriendiftheauthorhadnotcaredabouther?A.Shewouldhavelosthernewbestfriend.B.Shewouldhavekilledherselfthatnight.C.Shewouldhaverunawayfromherfamily.D.Shewouldhavestayedinhospitalforalongtime.7.Whatlessoncanwelearnfromthestory?A.Alwayscareaboutyourfriends. B.Don’tcareaboutothers’opinions.C.Neveroweyourfriendstoomuch. D.Trytobeascoolasothers.【答案】4.D5.C6.B7.ACAdamisafreshmanatseniorhighschool.Transitioningfromjuniorhightoseniorhighisarealchallengeforhim,andthefirstweekwassomewhatconfusing.First,hehadtocarefullydecideonhiscourses.Withtheschooladviser’shelp,hechosemaths,English,chemistry,worldhistory,andChinese.HeknowsChineseistoughbuthopestobefluentbygraduation.HisadviseralsoremendedhesignsupforadvancedliteraturesincehelovesandexcelsatEnglish.Then,heneededtopickextracurricularactivities.Hetriedtojointheschoolfootballteam,butthecoachsaidhedidn’tplaywellenough.Thoughunhappy,hewon’tquitandplanstoimproveonhisowntomaketheteamnextyear.Instead,hejoinedavolunteerclub.EveryWednesday,theyworkatasoupkitchen,handingoutfoodtohomelesspeopleinthemunity.Adamrealizeshemuststudyharderasaseniorhighstudentandgetusedtomoreresponsibilities.He’sabitworriedaboutkeepingupwithclassmatesinadvancedcoursesandadaptingtoallthehomework.Still,he’shappytobethere.Heknowsstudyinghardisn’talwaysfun,butitwillpreparehimwellforuniversityorwhateveresinthefuture.8.WhatdidtheschooladviserhelpAdamdo?A.Choosehisextracurricularactivities. B.Choosesuitablecourses.C.Improvehisfootballskills. D.Prepareforuniversity.9.WhydidAdam’sadviserremendadvancedliteraturetohim?A.BecauseAdamwantstostudyChinesewell.B.BecauseAdamisinterestedinworldhistory.C.BecauseAdamlikesEnglishandisgoodatit.D.BecauseAdamplanstobealiteratureteacher.10.WhatdidAdamdoafterfailingtojointhefootballteam?AHegaveuponsports. B.Hejoinedavolunteerclub.C.Hestartedtolearnanothersport. D.Heaskedthecoachformoretraining.11.HowdoesAdamfeelaboutkeepingupwithotherstudentsinadvancedcourses?A.Veryconfident. B.Abitworried.C.Extremelyexcited. D.Totallyunconcerned.【答案】8.B9.C10.B11.BDLastsummer,Itooka5daytriptoLijiangwithmyfamily—itwasthemostunforgettabletravelexperienceI’veeverhad.Lijiang,inYunnanProvince,isfamousforitswellpreservedancienttownandbeautifulnaturalscenery.WearrivedinLijiangbyplaneonasunnymorning.Thefirstthingthatsurprisedmewasthefreshairandbluesky.UnlikethebusycityIliveinLijiangfeltquietandpeaceful.WecheckedintoasmallinnneartheAncientTownofLijiang.Theinnhadasmallyardwithredflowersandastonetable—weoftensattheretodrinkhotteaafteradayofwalking.Onthesecondday,wevisitedtheAncientTown.Ithasahistoryofover800years,withnarrowstonestreetsandtraditionalwoodenhouses.Alongthestreets,therearemanysmallshopssellinghandmadecrafts,likesilverjewelryandtiedyecloth.Mymomboughtabeautifultiedyescarf,andIpickedasmallwoodendollasasouvenir.Wealsowalkedalongthesmallriversthatrunthroughthetown—localpeoplecallthem“theveinsofLijiang.”O(jiān)nthefourthday,wetookabustoJadeDragonSnowMountain.Themountainiscoveredwithsnowallyearround,eveninsummer.Whenwegottothefootofthemountain,Ifeltalittlecold,soIputonathickcoat.Wetookacablecaruptoaviewingplatform,andtheviewwasamazing—whitesnowonthemountaintops,greenforestsbelow,andcloudsfloatingaroundus.Itooksomanyphotosthatmyphoneranoutofbattery!Onthelastday,wetriedlocalfoodinasmallrestaurant.WeateYunnanricenoodles,steamedbunswithmushrooms,andasweetdishmadeofpurplepotatoes.Everythingtasteddelicious,especiallythericenoodles—theywerespicybutfullofflavor.WhenweleftLijiang,Ifeltalittlesad.Thistripdidn’tjustletmeseebeautifulplaces;italsotaughtmeaboutdifferentculturesandlifestyles.IhopeIcanvisitLijiangagainsomeday.12.WhatisLijiangfamousfor?A.Busycitylife. B.Moderntallbuildings.C.Ancienttownandnaturalscenery. D.Hotanddryweather.13.Whatdidthewriter’smombuyintheAncientTown?A.Awoodendoll. B.Silverjewelry. C.Atiedyescarf. D.Athickcoat.14.HowdidthewritergettotheviewingplatformofJadeDragonSnowMountain?A.Bybus. B.Bycablecar. C.Onfoot. D.Bybike.15.Whatcanweknowfromthewriter’strip?A.Thewriterdidn’ttakeanyphotosduringthetrip.B.Thewritertriedlocalfoodonthefirstday.C.TheAncientTownofLijianghasahistoryofover800years.D.JadeDragonSnowMountainhasnosnowinsummer.【答案】12.C13.C14.B15.C第二節(jié)：(共5小題,每小題2.5分,共12.5分)閱讀下面短文,從短文后的選項中選出可以填入空白處的最佳選項。選項中有兩項為多余選項。DengYapingisoneofthemostfamoustabletennisplayersinhistory.Herstoryofoveringdifficultiesandachievingsuccesshasinspiredpeoplearoundtheworld.____16____BorninZhengzhouin1973,Dengstartedplayingtabletennisattheageof5.Herfather,aformertabletenniscoach,taughtherthebasicsofthesport.Evenasayounggirl,Dengshowedgreatpassionandtalentforthegame.Shepracticedforhourseveryday,evenwhenshefelttired.However,Dengfacedabigchallengeearlyinhercareer.____17____Manycoachesthoughtshewastooshorttobeatopplayer—sheonlygrewto1.5meterstall.Someeventoldherthatshewouldnevermakeitinprofessionaltabletennis.ButDengrefusedtogiveup.Shebelievedthathardworkcouldmakeupforherheight.____18____In1988,shejoinedtheChinesenationaltabletennisteam.There,shetrainedevenharderwithtopcoachesandteammates.Hereffortssoonpaidoff.Atthe1992BarcelonaOlympics,DengwonherfirstOlympicgoldmedal.Fouryearslater,shewontwomoregoldmedalsatthe1996AtlantaOlympics.Overhercareer,shewon18worldchampionshipsand4Olympicgoldmedals.____19____Afterretiringfromtabletennisin1997,Dengdidn’tstoppursuingnewgoals.Shewantedtoprovethatathletescouldsucceedinotherfieldstoo.ShewenttouniversitytostudyEnglish,eventhoughshehadonlyaprimaryschooleducationbefore.Later,sheearnedamaster’sdegreefromTsinghuaUniversityandaPhDfromtheUniversityofCambridge.Today,Dengcontinuestomakecontributionstosportsandeducation.____20____Sheoftengivesspeechestoyoungpeople,tellingthemtonevergiveupontheirdreams.Shealsoworkstopromotetabletennisaroundtheworld,helpingmorepeoplefallinlovewiththesport.DengYapingismorethanasportsstar—sheisalivinglegend.Herstoryshowsthatwithhardwork,determination,andastrongwill,anyonecanachievetheirdreams.A.Herhardworkfinallyledtosuccess.B.Sheusesherexperiencetoinspireothers.C.Let’slearnmoreaboutheramazingjourney.D.Shedecidedtobeeatabletenniscoachlikeherfather.E.Herheightbecameaproblemforhertabletenniscareer.F.Shewantedtohelpmoreyoungpeoplelearntabletennis.G.Afterretiring,Dengfocusedonhereducation.【答案】16.C17.E18.A19.G20.B第三部分語言運用(共二節(jié),滿分30分)第一節(jié)完形填空(共15小題;每小題1分,共15分)閱讀下面短文，從每題所給的A、B、C、D四個選項中選出可以填入空白處的最佳選項。Asa16yearoldhighschoolstudent,myteenagelifeislikeacolorfulbook—eachpageisfilledwithsmallchallengesandbigjoys.Everyweekday,myalarmringsat6:30a.m.Ijumpoutofbed,washupquickly,andhaveasimplebreakfastofmilkandbread.ThenIrushtothebusstopto____21____theschoolbus.IfI’mlate,I’llhavetowalk20minutestoschool,whichisreallytiring.Schoolstartsat8o’clock.Themorningclassesarealwaysbusy:mathwithdifficultequations,Chinesewithmovingpoems,andEnglishwherewepractice____22____shortstories.MyfavoriteclassisP.E.—weplaybasketballorrunontheplayground.Ithelpsme___23___aftersittingintheclassroomforhours.Duringthe10minutebreakbetweenclasses,Iusuallychatwithmybestfriends,TomandLucy.Wetalkaboutourfavoritesongs,sharefunnyjokes,orplanwhattoeatfor____24____.Lunchtimeisgreattoo—ourschoolcanteenservesdeliciousdisheslikefriedchickenandvegetablesoup.Wesittogether,eatandlaugh,makingthebusydayfeel____25____.Afterschool,Ihavedifferentthingstodo.OnMondaysandWednesdays,IgototheEnglishclubtoimprovemyspeakingskills.OnTuesdaysandThursdays,Ipracticetheguitarwithmyteacher.Fridaysarefor___26___—Igototheschoollibrarytofinishmyhomework.WhenIgethomearound7p.m.,mymomhasalreadyprepareddinner.Aftereating,Ispend1.5hoursonhomework.ThenIhave30minutesto____27____myfavoriteTVshoworreadanovel.Igotobedat10:30p.m.sharp—enoughsleephelpsmestayfocusedthenextday.Weekendsaremorerelaxing.OnSaturdays,Ioftengohikingwithmyfamily.Thefreshairandgreentreesmakemefeel____28____.OnSundays,ImeetTomandLucytoplaytennis.Sometimeswealsogotothecinematowatchanewmovie.Somepeoplesayteenagelifeis___29___becauseoftoomuchhomeworkandexams.ButIthinkit’sfulloffun.Thechallengesteachmetobehardworking,myfriendsbringmelaughter,andmyfamilygivesme____30____.Lastmonth,Ihadabigmathexam.Istudiedforaweek,butIstillfeltnervous.TomandLucyhelpedmereviewthekeypoints,andmymomencouragedmeeverynight.Finally,Igotagoodgrade.Thatmomentmademerealize:teenagelifeisn’tjustaboutstudying—it’sabout____31____withthepeoplewhocareaboutyou.Iknowmyteenageyearswillpassquickly.SoItrytoenjoyeveryday:listeningtotheteachercarefullyinclass,laughingwithfriendsduringbreaks,andhuggingmyparentsafteralongday.Thesesmallmoments____32____tomakemylifewonderful.SometimesIfeeltired,butwhenIlookbackattheday,Ialwaysfindsomethinggood.Maybeit’sagoodgrade,afriend’sjoke,orawarmmealathome.Theselittlejoysmakeallthehardwork____33____it.Myteenagelifeisn’tperfect,butit’sreal.It’satimeoflearning,laughing,andtryingnewthings.I’mgratefulforthisperiodofmylife,andI’mlookingforwardto____34____morefunmomentsinthefuture.Thisismyteenagelife—busy,butbrilliant.Ibelieveitwillbeoneofthemost____35____partsofmylifewhenIgrowup.21.A.catch B.miss C.avoid D.stop22.A.writing B.dancing C.singing D.painting23.A.relax B.worry C.cry D.shout24.A.breakfast B.lunch C.dinner D.snack25.A.boring B.difficult C.warm D.scary26.A.working B.studying C.cleaning D.reading27.A.watch B.break C.build D.sell28.A.sad B.happy C.angry D.sleepy29.A.easy B.free C.stressful D.useless30.A.cold B.warmth C.trouble D.noise31.A.givingup B.fallingdown C.growingup D.showingoff32.A.addup B.takeoff C.turndown D.putaway33.A.useless B.worth C.boring D.difficult34.A.forgetting B.missing C.experiencing D.ending35.A.forgettable B.important C.mon D.boring【答案】21.A22.A23.A24.B25.C26.B27.A28.B29.C30.B31.C32.A33.B34.C35.B閱讀下面材料，在空白處填入適當(dāng)?shù)膬?nèi)容（1個單詞）或括號內(nèi)單詞的正確形式。Manystudentsfearedmathssubject,andIwasamongthem.OnceIfailed____36____themathematics,Iwas____37____(annoy),Myfriendsstartedmakingfunofme.Iwas____38____(luck)thatmymotherwasamathsteacher.Shealwayshelpsme,butIdidn’ttakethatseriously.Whenmymother____39____(tell）thatIdidn’tpassthemathssubject,shegotshocked.But____40____（fortunate）,shedidn’tshoutatme.Instead,shegaveme____41____inspirationalspeech.Lateronshestartedteachingmemathematics.Shetaughtme____42____(play)withmathsandreallyIenjoyedalot,fromwhichmathsbecamemyfavouritesubject.NowIalsoteachthosefriendswhoreallyfearmaths.Theythinkthatmathssubjectsisverydifficultandithaslotsofformula（公式）toremember.Butmymothertaughtmemathsinan____43____(interest)way.Iusedthattechniquetosolveproblems.Fromthismy____44____(confident)hasincreasedandI’mhappythatmostdifficultsubjecthasbeeagameforme.Beinganengineerismyambition,_____45_____maysupportmethroughhardshipsandsetbacks.【答案】36.in37.annoyed38.lucky39.wastold40.fortunately41.an42.toplay43.interesting44.confidence45.which第四部分寫作(滿分15分)46.假如你是李華，是學(xué)校英文報“Advice”欄目的編輯。你收到一封署名為Jack的來信。信中該同學(xué)訴說了自己的困惑：進(jìn)入高中后經(jīng)常感到壓力（stress）大，晚上睡不好，使正常的學(xué)習(xí)和生活受到了影響。請用英文給該同學(xué)寫一封回信。內(nèi)容包括：1.表示理解并給予安慰；2.提出建議并說明理由。（至少兩條建議）注意1.詞數(shù)100左右；2.可以適當(dāng)增加細(xì)節(jié)，以使行文連貫。DearJack,_____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________Yourssincerely,LiHua【答案】例文DearJack,I’mtrulysorrytohearthatyou’vebeenstrugglingwithstressandpoorsleepsincestartingseniorhighschool.Actually,lotsofstudentsfeelthesamewayasyoudowhentheystepintoanewstage,soyou’renotalone.There’snoneedtobetooanxious.Hereareacoupleofsuggestionsforyou.First,it’sagoodideatomakeadetaileddailystudyplan.Byorganizingyourstudytasksclearly,youcanavoidthefeelingofbeingstressful.Second,trytotakepartinsomephysicalactivities,likejoggingorplayingbasketballafterschool.Exerciseisagreatwaytoreducetension,makingiteasierforyoutofallasleepatnight.Ihopethesetipscanbringyousomereliefandhelpyougetbacktoagoodlearningandlivingconditionsoon.Yourssincerely,LiHua第五部分基礎(chǔ)知識測試(滿分25分)第一節(jié)根據(jù)中文提示拼寫單詞的適當(dāng)形式。(每空1詞，1空1分，共10分)47.Actually,Ifoundthejobinthepanywasreally________(有挑戰(zhàn)性的).(根據(jù)漢語提示單詞拼寫)【答案】challenging48.Adamfelt________(焦慮的)aboutkeepingupwiththeotherstudentsinhisadvancedcoursesatseniorhighschool.(根據(jù)漢語提示單