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