Predicate-argument structures of PropBank, VerbNet and FrameNet. The scheme to assign predicate-argument structures can be varied among different projects due to their different focused applications. This figure shows the differences of predicate-argument structures defined from these three projects: PropBank [22, 23], VerbNet  and FrameNet . Similar scheme as PropBank is applied to our PASBio project. Discussion about the reason why we are interested in PropBank scheme is discussed in the main text.