Al arquitecto se le olvidó el plano. Sin embargo, construyó el edificio.The architect accidentally forgot the plan. However, he built the building.Breakdown of Al arquitecto se le olvidó el plano. Sin embargo, construyó el edificio.atoleto him / to her / to you (formal) / him (direct object, male person)sehimself / herself / themselves (reflexive)el edificiothe building