What is the {subject has role} and the {has effect} of {Nitrous_oxide} ?
What is the role and effect of nitrous oxide?
What is Nitrous oxide subject role and its effect"
SELECT ?c ?k WHERE { resource:nitrous_oxide property:has_effect ?k . resource:nitrous_oxide property:subject_has_role ?c }
 SELECT ?ans_1 ?ans_2 WHERE { ?statement1 <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q905750> . ?statement1 <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P2868> . ?statement1 <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> ?ans_1. ?statement2 <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q905750> . ?statement2 <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P1542> . ?statement2 <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> ?ans_2. } 
SELECT ?ans_1 ?ans_2 WHERE { wd:Q905750 wdt:P2868 ?ans_1 . wd:Q905750 wdt:P1542 ?ans_2 }
Nitrous oxide exposure inhalational anaesthetic Nitrous oxide exposure non-opioid analgesic Nitrous oxide exposure nitric oxide donors