Taking the unigram feature not as an example, we have p k = [0.66, 0.34] and q k = [0.31, 0.69], for a KL-divergence of 0.25: the likelihood of this word being shared between two sentence is strongly dependent on whether the sentences are paraphrases.
the feature then has p k = [0.33, 0.67] and q k = [0.32, 0.68], for a KL-divergence of 3.9 × 10 −4 .