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.

Whatdoyouthinkofhismotionthatwe__________aplayattheEnglishevening?

这件工作我不满意。(satisfy)

Nothingcanstopusnow,__________?