Take the sentence pair in Figure 2 as an example, two initial phrase pairs PP 1 = "那 只 蓝色 手提包 ||| 那 个 蓝色 手提包" and PP 2 = "对 那 只 蓝色 手提包 有 兴趣 ||| 很 感 兴趣 那 个 蓝色 手提包" are identified, and PP 1 is contained by PP 2 , then we could form the rule: 对 X 1 有 兴趣  很 感 兴趣 X 1 to have interest very feel interest The extracted paraphrase rules aim to rewrite the input sentences to an MT-favored form which may lead to a better translation.
it is risky to directly replace the input sentence with a paraphrased sentence, since the errors in automatic paraphrase substitution may jeopardize the translation result seriously.