... = 64N = 2048331Proceedings of the 47th Annual Meeting of the ACL and the 4th IJCNLP of the AFNLP, pages 324–332,Suntec, Singapore, 2-7 August 2009.c2009 ACL and AFNLP1 2 3 1123{ }324 ... 128N330X a → X1, X1Xb→ X1 X2, X1X2Xc→ Xd→ X1 , X1Xe→ , X a XdXbX a XbXd≺X a ≺ Xb≺ Xc≺ Xd≺ XeXd≺ X a ≺ Xb≺ Xc≺ ... ❄❳❳❳❳❳③✘✘✘✘✘✾❄❄ ❄ ❄X a ⇒ Xb, Xb⇒ Xc Xd, XcXd⇒ Xd, Xd⇒ Xe , Xe⇒ , Xd⇒X a , X a ⇒ Xb ...