What is the {human} for {mother} of {Bill Gates}
What is the name of Bill Gate's mother?
Who was Bill Gates's mother?
SELECT DISTINCT ?x WHERE { resource:Bill_Gates property:mother ?x . ?x rdf:type ontology:human }
select distinct ?obj where { ?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q5284> . ?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P25> . ?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> ?obj . ?obj <http://www.wikidata.org/entity/P31> <http://wikidata.dbpedia.org/resource/Q5> } 
 select distinct ?obj where { wd:Q5284 wdt:P25 ?obj . ?obj wdt:P31 wd:Q5 } 
Mary Maxwell Gates