Haveyoueverwonderedwhybirdssing?Maybeyouthoughtthattheywerejusthappy.Afterall，youprobablysingorwhistlewhenyouarehappy.Somescientistsbelievethatbirdsdosingsomeofthetimejustbecausetheyarehappy.However

Haveyoueverwonderedwhybirdssing?Maybeyouthoughtthattheywerejusthappy. Afterall，youprobablysingorwhistlewhenyouarehappy.

Somescientistsbelievethatbirdsdosingsomeofthetimejustbecausetheyarehappy.However，theysingmostofthetimeforaverydifferentreason.Theirsingingisactuallyawarningtootherbirdstostayoutoftheirterritory.

Doyouknowwhata’territory’is?Aterritoryisanareathatananimal，usuallythemale，claims(声称)asitsown.Onlyheandhisfamilyarewelcomethere.Nootherfamiliesofthesamekindarewelcome.Yourgardenandhouseareyourterritorywhereonlyyourfamilyandfriendsarewelcome.Ifastrangershouldenteryourterritoryandthreaten(威胁)you，youmightshout.Probablythiswouldbeenoughtofrightenhimaway.

Ifso，youhaveactuallyscaredthestrangerawaywithouthavingtofighthim.Abirddoesthesamething.Butheexpectsanoutsideralmostanytime，especiallyatnesting(筑巢)season.Soheisscreamingallthetime，whetherhecanseeanoutsiderornot.Thisscreamingiswhatwecallabird’ssong，anditisusuallyenoughtokeepanoutsideraway.

Birdssingloudestinthespringwhentheyaretryingtoattractamateandwarnothersnottoentertheterritoryoftheirs..

Youcanseethatbirdshavealanguageoftheirown.Mostofithastodowithattractingmatesandsettingupterritories.

【小题1】Somescientistsbelievethatmostofthetimebird’ssingingisactually_______.

A．awayofwarningB．anexpressionofhappinessC．anexpressionofangerD．awayofgreeting【小题2】Whatisabird’s"territory"?.A．Aplacewherefamiliesofotherkindsarenotaccepted.B．AplacewhereabirdmayshutatthetopofitsvoiceC．Anareaforwhichbirdsfightagainsteachother.D．Anareawhichabirdconsiderstobeitsown.【小题3】Whydobirdskeeponsingingatnestingseason?A．Becausetheywanttoinvitemorefriends.B．Becausetheywanttofindoutsidersaround.C．Becausetheirsinginghelpsfrightenoutsidersaway.D．Becau