For the relation-specific words for each relation (except Other), we use words (see Table 1) derived mainly from Marcu (1997)'s list of discourse markers.
type 4 (φ 4 ) the final set of features (used only in model 3) are present to help the model learn connections between the words in the question and the relation type r. we check if the interrogative word in the question matches the class represented by r. For instance, the word why matches the Causal relation.