We list six inconsistent configurations in literature, which lead to difficulties for fair comparison. Most work uses the development set to select hyperparameters (Lample et al., 2016; <cite>Ma and Hovy, 2016</cite>) , while others add development set into training set (Chiu and Nichols, 2016; Peters et al., 2017) . Different from <cite>Ma and Hovy (2016)</cite> and Liu et al. (2018) , choose a different data split on the POS dataset.