before_sent:  Using our human-evaluation datasets, we show that existing metrics based on n-gram similarity  do not correlate with human judgments.
before_sent_with_intent: <clarity>  Using our human-evaluation datasets, we show that existing metrics based on n-gram similarity  do not correlate with human judgments.
after_sent:  Using our human-evaluation datasets, we show that existing metrics based on n-gram similarity metrics do not correlate with human judgments.