usedtobeoneofthemost的精選

問題詳情：    Thepassengerpigeon(旅鴿)usedtobeoneofthemostcommonbirdsontheearth.Acenturyago,theybecameextinct（滅絕）.ScientistBenNovakisworkingtobringthebirdsback.Here,heexplainstouswhyweshouldbringpas...