import tensorflow as tf

    feature_emb = tf.concat(feature_emb_list, 2) # [k, c, emb]
    feature_emb = tf.nn.dropout(feature_emb, self.dropout) # [k, c, emb]

    target_emb = tf.expand_dims(top_span_emb, 1) # [k, 1, emb]
    similarity_emb = top_antecedent_emb * target_emb # [k, c, emb]
    target_emb = tf.tile(target_emb, [1, c, 1]) # [k, c, emb]
