Theaveragecomputeruserhasbetween5and15username/passwordcombinationstologindifferentkindsofaccounts．Somedemandyouuseaspecificnumberofsymbolsanddigits，whileothersrequireyoutochangeyourpasswordevery60days．Thefeelingofconfusionresultingfrommemorizingtheselogininformationhasgrownsocommonthatitactuallyhasaname：passwordfatigue（疲劳）．

Havingtoremembersomanydifferentpasswordsisannoying，butitcanalsobedangerous．Becauseitisvirtuallyimpossibletorememberauniquepasswordforeachoftheseaccounts，manypeopleleavehandwrittenlistsofusernamesandpasswordsonornexttotheircomputers．

（71）___Whilethesepracticesmakeiteasiertorememberlogininformation，theyalsomakeiteasierforthievestohackintoaccounts．

SingleSign-On（SSO）confirmationandpasswordmanagementsoftwarecanhelpsolvethisproblem．WithSSO，usersonlyneedtorememberonepasswordtologintothemainsystem．

（72）___SSOsoftwareistypicallyusedbylargecompanies，schools，orlibraries．

（73）___IfauserlosesorforgetsthepasswordrequiredtologintoSSOsoftware，theuserwillthenloseaccesstoalloftheapplicationslinkedtotheSSOaccount．Userswhorelyonpasswordmanagementsoftwarefacethesameproblems．

Althoughmostwebsitesornetworksystemsallowuserstorecoverorchangelostpasswordsbyprovidingemailaddressesoransweringaprompt（提示），thisprocesscanwastetimeandcausefurtherfrustration．Whatismore，recoveringaforgottenpasswordisonlyatemporarysolution．

（74）___

Somecomputerscientistshavesuggestedcomputersrelyonbiometrics（生物测定学）．（75）___ Theuseofbiometricsraisesquestionsconcerningprivacyandcanalsobeexpensivetopractice．

Softwareengineersandcomputersecurityexpertsarestillsearchingforthecuretopasswordfatigue．Untiltheyfindtheperfectsolution，however，everyonewillsimplyhavetorelyonthepasswordsystemcurrentlyinplace．

A．Itdoesnotaddressthelargerproblemofpasswordfatigue．

B．Thesesoftwareprogramshavebeenbuiltintomanymajorwebbrowsers

C．Theproblemwithpasswordmanagementsoftwaremakesusersfeelpowerless．

D．The