In both Niu [11] and Dang's <cite>[10]</cite> work, topical features as well as the so called collocational features were used. However, as discussed in Section 2, they both used bi-gram cooccurrences as the additional local features. Thus instead of using co-occurrences of bigrams, we take the true bi-gram collocations extracted from our system and use this data to compare with bi-gram co-occurrences to test the usefulness of collocation for WSD.