Question: How many rivers start in an English speaking country?
SPARQL query:
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX onto: <http://dbpedia.org/ontology/>
SELECT DISTINCT COUNT(?uri) WHERE { ?x onto:officialLanguage <http://dbpedia.org/resource/English_language> . ?uri onto:sourceCountry ?x  . ?uri rdf:type onto:River}