Before revision:  We conduct experiments on the benchmark dataset FewEvent and the experimental results show that the tagging based methods are better than existing pipeline and joint learning methods. In addition, the proposed PA-CRF  achieves the best results on the public dataset .
After revision:  We conduct experiments on the benchmark dataset FewEvent and the experimental results show that the tagging based methods are better than existing identify-then-classify models and our PA-CRF achieves the best results on the public dataset .