翻译：marketshare

完型填空(本大题共10小题，每小题1分，共10分)从选项中选择一个最适合短文的选项，错选、多选或未选均无分。

Joggingisbecomingoneofthe___21___growingactivitiesinthenation.Morepeoplearestartingjogeachyear.This,however,isarecentoccurrence.Itwasnotlongago__22____joggerswereraresight.Somepeoplethoughtthattheylookedquitestrange.As__23____peoplebeganjoggingthesightofthembecamemorecommon.Therearemanyreasons___24___apersontotakeupjogging.First,itisagoodformofexercise.Thisis__25____itinvolvestheuseofmanypartsofthebody.Theexercisingoftheheartisofgreatbenefit.Thisisoneofthemostimportantpartsofthehumanbody.Iftheheartdoesnotgettheneededexercise,seriousproblemscanoccur.___26___reasonforjoggingisforenjoyment.___27___beinggoodforpeople,itcanalsobeverymuchfun.Partofthefunofjoggingcomesfromtheopportunityitprovidesformeetingotherpeoplewhoenjoyit.One___28___thatshouldbeconsidered___29___apersontakesupjoggingasaformofexerciseofenjoymentisthatitisnotforeveryone.Peopleshouldfirstcheck30theirdoctorsandbepreparedtofindanotherformofexerciseifjoggingisnotrecommended.

21.A.fastestB.quickestC.mostD.best

22.A.whenB.whileC.thatD.as

23.A.manyB.thoseC.moreD.the

24.A.ofB.withC.forD.in

25.A.thatB.whyC.reasonableD.because

26.A.AB.OtherC.TheotherD.Another

27.A.ExceptB.ExceptforC.BesidesD.Regardlessof

28.A.matterB.eventC.thingD.occurrences

29.A.ofB.thatC.whatD.when

30.A.outB.overC.onD.with

__________someofthesuggestionsproveofvaluetoyouaswell?

Ifyoudonotfindtherequiredinformationusingthetipsfromtheprevioussection,thenyouneedtoconsultanonlineservicetofindthepieceofinformationyouwerelookingfor.Threedifferenttypesofserviceshavebeenestablishedovertheyears:crawlers,directoriesandmetasearchengines.Thefirstcrawlerwascreatedbackin1993.ItwascalledtheWorldWideWorm.Itcrawledfromonesitetothenextandindexedallpagesbysavingthecontentofthewebpagesintoahugedatabase.Crawlersorspidersvisitawebpage,readit,andthenfollowlinkstootherpageswithinthesiteandevenfollowlinkstoothersites.Webcrawlersreturntoeachsiteonaregularbasis,suchaseverymonthortwo,tolookforchanges.Everythingacrawlerfindsgoesintoadatabase,whichpeopleareabletoquery.TheadvantageofthewebcrawlersisthattheyhaveanextensivedatabasewithalmostthecompleteInternetindexedinit.Thedisadvantageisthatyougetthousandsofwebpagesasaresponseforalmostanyrequest.Webdirectoriesworkalittledifferently.Firstofalltheycontainastructuredtreeofinformation.Allinformationenteredintothistreeiseitherenteredbythewebmasterwhowantstoannouncehisnewwebpageorbythedirectorymaintainerwholooksatthewebpagessubmitted.ThedirectorieswherewebmasterscansubmitboththeURL(UniformResourceLocator)andthedescriptionnormallycontainmoremisleadinginformation.Gettingintomostwebdirectoriesisacombinationofluckandquality.Althoughanyoneisabletosubmitawebpage,thereisnoguaranteethatacertainpagewillbeincluded.Somedirectorieschargeforsubmission,whichisbasicallyarip-off.Somecrawlersmaintainanassociateddirectory.Ifyoursiteisinthedirectory,therankingofyourwebsitenormallywillbehigher,asitisalreadypre-classified.Manydirectoriesworkwithcrawlerstogether,inordertodeliverresults,whennothingcanbefoundinthedirectory.MetasearchenginesdonothaveadatabasewithURLsanddescriptions.Insteadtheyhaveadatabaseofsearchengines.Ifyouenteryourkeywordsintoametasearchengineitwillsendoutrequeststoallthedirectoriesandcrawlersithasstoredinitsdatabase.ThemetasearchengineswithamoresophisticatedapplicationinthebackgroundareabletodetectdoubleURLswhichcomebackfromthevarioussearchenginesandpresentonlyasingleURLtothecustomer.

34.Crawlerisakindof__________.

A.wormB.searchengineC.serviceD.directory

35.ThedisadvantageofCrawleristhatit__________.

A.providesacompletedatabase

B.takestoomuchtimetofindtheneededinformation

C.providestoomuchuselessinformation

D.givesresponsetoeveryquest

36.Whocaninputinformationtothewebdirectories?

A.Onlywebmasters.

B.Bothdirectorymaintainersandwebmasters.

C.Anyonewhowantstoannounceawebpage.

D.Anyonewhohasfoundanewwebpage.

翻译：invain