https://w3id.org/framester/conceptnet5/data/en/learn_skill <https://w3id.org/framester/conceptnet5/schema/HasPrerequisite> <https://w3id.org/framester/conceptnet5/data/en/practice_that_skill> <https://w3id.org/framester/conceptnet5/schema/MotivatedByGoal> <https://w3id.org/framester/conceptnet5/data/en/earn_live> risorse dalla linked data cloud