Inaworldwhere itseemswealreadyhavetoomuchtodo,andtoomanythingstothinkabout,it seemsthelastthingweneedissomethingnewthatwehavetolearn. Butusecasesdo solveaproblemwithrequirements:with(71)declarativerequirementsit'shardtodescribestepsandsequencesof events. Usecases,stated simply,allowdescriptionofsequencesofeventsthat,takentogether,leadto asystemdoingsomethinguseful.Assimpleasthissounds,thisisimportant. Whenconfrontedonlywithapileofrequiements,it'soften(72)tomakesenseofwhattheauthorsofthe requirementsreallywantedthesystemtodo.Intheprecedingexample,usecases reducetheambiguityoftherequirementsbyspecifyingexactlywhenandunder whatconditionscertainbehavioroccurs;assuch,thesequenceofthebehaviorscan beregardedasarequirement.Usecasesareparticularlywellsuitedtocapture approaches.Althoughthismaysoundsimple,thefactisthat(73)requirementcaptureapproaches,withtheir emphasisondeclarativerequirementsand"shall" statements,completelyfailtocapturefailtocapturethe(74)ofthesystem'sbehavior.Usecasesarea simpleyetpowerfulwaytoexpressthebehaviorofthesysteminwaythatall stakeholderscaneasilyunderstand. But,like anything,usecasescomewiththeirownproblems,andasusefulasthey are,theycanbe(75).Theresultissomethingthatisasbad,ifnotworse,thattheoriginal problem.Thereinit'simportanttoutilizeusecaseseffectivelywithout creatingagreaterproblemthantheoneyoustartedwith.
A.impossible B.possible C.sensible D.practical正确答案A
