before_sent:   Tagging, or using gates, has been used to enable translation models to distinguish between synthetic and natural data.
before_sent_with_intent: <meaning-changed>   Tagging, or using gates, has been used to enable translation models to distinguish between synthetic and natural data.
after_sent:  The method was not able to utilize the available huge amount of monolingual data because of the inability of models to differentiate between the authentic and synthetic parallel data. Tagging, or using gates, has been used to enable translation models to distinguish between synthetic and natural data.