The NER dataset has been standardly split in Tjong Kim Sang and De Meulder (2003 (Toutanova et al., 2003; Santos and Zadrozny, 2014; Ma and Hovy, 2016; <cite>Liu et al., 2018)</cite> , we adopt the standard splits by using sections 0-18 as training set, sections 19-21 as development set and sections 22-24 as test set.