We concatenate the word embedding e t , answer position embedding a t and lexical features embedding l t as input ( Then a bidirectional LSTM is used to produce a sequence of hidden states (h 1 , ..., h T ).
assuming m+1, ..., m+a is the index of given answer span in the input sentence, based on the corresponding featurerich hidden states (h m+1 , ..., h m+a ), we calculate the question type hidden states as follow: where l m+j is the corresponding lexical features.