∵CD⊥AB,BE⊥AC,垂足分别为D、E,且AO平分∠BAC,
∴△ODA≌△OEA,
∴∠B=∠C,AD=AE,
∴△ADC≌△AEB,
∴AB=AC,
∴△OAC≌△OAB,
∴△COE≌△OBD.
故填4.