In Table1, the first column shows possible categories of dependency relations from the head, and rules on corresponding dependents are listed in the second column. These rules mainly use features about single node (including the word’s part-of-speech) and relations between dependency pairs. These rules are also applied to some special phrase structures such as passive structure (e.g. rule3 and rule 4) and coordinate construction (e.g. rule 7 and rule 9).
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During the procedure of recognizing event-arguments, we firstly extract the head verb as the predicate, traverse its child nodes and make corresponding rules effective according to the dependency category. From the instance sentence in Figure 1, we extract an event structure “[Subj teacher] [Pre criticize] [Obj student]” successively using rule 1, rule 3, and rule 10.