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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.
Inwhatseemsliketheprehistorictimesofcomputerhistory;theearth’spostwarera,therewasquiteawidespreadrumorthatcomputerswouldtakeovertheworldfrommanoneday.Alreadytoday,lessthanfiftyyearslater,ascomputersarerelievingusofmoreandmoreoftheroutinetasksinbusinessandinourpersonallives,wearefacedwithalessdramaticbutnotlessforeseenproblem.Peopletendtobeover-trustingofcomputersandarereluctanttochallengetheirauthority.Indeed,theybehaveasiftheywerehardlyawarethatwrongbuttonsmaybepushed,orthatacomputermaysimplymalfunction.Obviously,therewouldbenopointininvestinginacomputerifyouhadtocheckallitsanswers,butpeopleshouldalsorelyontheirowninternalcomputersandcheckthemachinewhentheyhavethefeelingthatsomethinghasgonewrong.Questioningandroutinedouble-checksmustcontinuetobeasmuchapartofgoodbusinessastheywereinpre-computerdays.Maybeeachcomputershouldcomewiththewarning:forallthehelpthiscomputermayprovide,itshouldnotbeseenasasubstituteforfundamentalthinkingandreasoningskills.
37.Accordingtothepassage,theauthorwouldprobablydisapproveof__________.
A.investmentincomputers
B.completedependenceoncomputers
C.double-checkoncomputers
D.theuseofcomputer
38.Intheauthor’sopinion,peopleshould__________.
A.bereasonablydoubtfulaboutcomputers
B.usecomputersforbusinesspurposesonly
C.substitutecomputersforbasicthinking
D.checkalltheiranswerswhenusingcomputers
39.Whatissuggestedinthispassage?
A.Computerwon’tchangeourpersonallives.
B.Computercancreateunforeseenproblems.
C.Computerhastakencontroloftheworld.
D.Computercannotaffectourbusinesses.
40.Whatisthemainpurposeofthispassage?
A.Tolookbacktotheearlydaysofcomputers.
B.Toexplainwhattechnicalproblemsmayoccurwithcomputers.
C.Todiscourageinvestmentincomputers.
D.Towarnagainstamentallylazyattitudetowardscomputers.
