阅读理解

Itseemslikeeveryyearbringsanewoutbreakofsickness.Recentresearchtellsushowdiseasesspreadfrompersontoperson.Anditalsogivesusanideahowwecanspreadsomethingbetterthandiseases.

AnauthorcalledMalcomGladwellrecentlypublishedabookexplaininghowtheprocessworks.Weusuallythinkofaepidemic（流行病）asaforceofnaturethatrollsoveranyoneinitsway.Infact,itstartswithasinglepersonorveryfewpeople.Thesepeopletravelaroundandinfect（传染）smallgroupsindifferentplaces.Whenenoughofthesegroupsareinfectedthenthediseasesuddenlyseemstobeeverywhere.Gladwellalsofoundthattheprocessofinfectionwasnotjustlimitedtodisease.Italsoaffectstheworldofideas.

Theprocesscanbeseeninbooksandfashion.Socalled“undergroundbestsellers”arenotpushedtowardsthepublic.Theyspreadthroughhundredsofsmallreadinggroupsuntilthedaywheneverybodyyouknowseemstohaveacopy.Agroupofyoungpeoplemaydecidetowearanitemofclothingsimplybecausenoneelseiswearingit.Designerswhomonitorstreetfashionthenpickuptheideaandspreadit.Finallyeveryoneiswearingit.

NewYorkisoftendescribedasanunfriendlyplace.Peoplearetoobusylookingafterbusinesstolookaftereachother.Intheearly1990s,oneunknownpersondecidedtoperformatleastonekindactaday.Thiscaughtonwithhisorherfriends.Thenewspapersnoticedthetrend（趋势）.NewYorkbecamefullofpeoplesmilingandcarryingeachother'sbags.

Thesuccessoftrendslikethisfitsinwithothersocialphenomena（现象）.Oneisthe80/20rule.Thiswasinventedbyeconomistswhonoticedthatinanysituation20percentofthepeopledid80percentofthework.Anotheristhe“bystanderproblem”.Psychologistsnoticedthatinaccidentswherealargenumberofpeoplewerearound,noonesteppedforwardtohelp.Eachpersonsupposedthatsomeoneelsewoulddosomething.Whentherewerelesspeoplepresent,moreofthemdecidedtoofferhelp.

Whatallthisprovesisthepowerofindividuals（个人）andsmallgroups.The“epidemicmodel”couldbeagreatwayofmakingabusinessgroworspreadinganidea.Asmallstartcanmakeabigdifference.

1．Thewriter'smainpurposeistotellus________.

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A．howdiseasesspread

B．howid