For each KG, we classify its set of relations into two categories based on the answer set cardinality.
we define the metric ξ r as the average answer set cardinality of all queries with topic relation r. We count r as a "to-many" relation if ξ r > 1.5, which indicates that most queries in relation r has more than 1 correct answer; we count r as a "to-one" relation otherwise, meaning most queries of this relation have only 1 correct answer.