4 Sagan for MT evaluation Sagan for MT evaluation is based on a core devel-opment to approach the Semantic Textual Similari-ty task ( STS ) . The pilot task STS was recently defined in Semeval 2012 ( Aguirre et al , 2012 ) and has as main objective measuring the degree of semantic equivalence between two text fragments . STS is related to both Recognizing Textual En-tailment ( RTE ) and Paraphrase Recognition , but 54