∵BE=CD,∠BEO=∠CDO,∠BOE=∠COD,∴△BEO≡△CDO.
∴EO=DO,BO=CO,∴CO+EO=BO+OD,即BD=CE.又∵∠BAD=∠CAE,∠ADB=∠AEC,∴△ABD≡△ACE.∴AE=AD