下面是百度里的回答

　　Halloween

　　October31st(westerncountries)

　　Halloweenisoneoftheoldestholidayswithoriginsgoingback

　　thousandsofyears.Theholidayhashadmanyinfluencesfrommany

　　culturesoverthecenturies.FromtheRoman'sPomonaDay,tothe

　　CelticfestivalofSamhain,totheChristianholidaysofAllSaints

　　andAllSoulsDays.

　　HundredsofyearsagoinwhatisnowGreatBritainandNorthern

　　France,livedtheCelts(凯尔特人),whoworshipped(崇拜)natureandhad

　　manygods,withthesungodastheirfavorite.Theycelebratedtheir

　　NewYearonNovember1stwhichwasmadeeveryyearwithafestival

　　andmarkedtheendofthe"seasonofthesun"andthebeginningof

　　"theseasonofdarknessandcold."

　　OnOctober31stafterthecropswereallharvestedandstoredfor

　　thelongwinterthecookingfiresinthehomeswouldbeextinguished

　　(消失).TheDruids,theCelticpriests,wouldmeetinthehilltopin

　　thedarkoakforest(oaktreeswereconsideredsacred).Theywould

　　lightnewfiresandoffersacrificesofcropsandanimals.Asthey

　　dancedaroundthefires,theseasonofthesunpassedandtheseason

　　ofdarknesswouldbegin.

　　WhenthemorningarrivedtheDruidswouldgiveanemberfromtheir

　　firestoeachfamilywhowouldthentakethemhometostartnew

　　cookingfires.Thesefireswouldkeepthehomeswarmandfreefrom

　　evilspirits.

　　TheNovember1stfestivalwascalledSamhain(pronounced"sow-en").

　　Thefestivalwouldlastfor3days.Manypeoplewouldparadein

　　costumesmadefromtheskinsandheadsoftheiranimals.This

　　festivalwouldbecomethefirstHalloween.

　　TheCelticswouldcarryalantern(灯笼)whentheywalkedontheeve

　　ofOctober31.Theselanternswerecarvedoutofbigturnips(大头菜)

　　andthelightswerebelievedtokeeptheevilspiritsaway.Children

　　wouldcarvefacesintheturnips.Thesecarvedturnipswerecalled

　　"jack-o-lanterns.

　　Itissaidthatthe"jack-o-lantern"gotitsnamefromastingy

　　(吝啬的)andmeanoldman,namedJack,whowhenhediedwastoomeanto

　　getintoheaven.WhenJackwenttohellhewasmeetbytheDevilwho

　　gavehimapieceofburningcoalandsenthimaway.Jackplacedthe

　　burningcoalinaturniptouseasalanterntolighthisway.The

　　legendsclaimthatJackisstillwalkingwiththelanternlooking

　　foraplacetostay.

　　WhentheearlysettlerscametoAmericatheyfoundthebiground

　　orangepumpkin.Beinglargerandmuchmorecolorfulthanturnips,

　　thepumpkinmadegreat"jack-o-lanterns".Eventuallythepumpkin

　　wouldreplacetheturnip.EventuallythePumpkinwouldbecomethe

　　mostwidelyrecognizedsymbol（象征）oftheHalloweenholiday.

　　Thehistoryof"Trick'O'Treating"canbetracedback(追溯)tothe

　　earlycelebrationsofAllSoul'sDayinBritain.Thepoorwouldgo

　　beggingandthehousewiveswouldgivethemspecialtreatscalled

　　"soulcakes".Thiswascalled"goinga-souling",andthe"soulers"

　　wouldpromisetosayaprayerforthedead.

　　Overtimethecustomchangedandthetown'schildrenbecamethe

　　beggars