import tensorflow as tf

            ch_emb = tf.reshape(ch_emb, [N, PL, ch_emb.shape[-1]])
            qh_emb = tf.reshape(qh_emb, [N, QL, ch_emb.shape[-1]])

            c_emb = tf.nn.dropout(tf.nn.embedding_lookup(self.word_mat, self.c), 1.0 - self.dropout)
            q_emb = tf.nn.dropout(tf.nn.embedding_lookup(self.word_mat, self.q), 1.0 - self.dropout)

