Question: Which president of United States had vice president as John Adams?
SPARQL:
SELECT DISTINCT ?uri WHERE {?uri <http://dbpedia.org/ontology/vicePresident> <http://dbpedia.org/resource/John_Adams>  . ?uri <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://dbpedia.org/ontology/OfficeHolder>}