Question: Which countries have German as the official language, that is the location contains and airport that serves the location of Kleve district ?
Answer(s):
answer: Germany

SPARQL query:
PREFIX ns: <http://rdf.freebase.com/ns/>
SELECT DISTINCT ?x
WHERE {
FILTER (?x != ns:m.04306rv)
FILTER (!isLiteral(?x) OR lang(?x) = '' OR langMatches(lang(?x), 'en'))
ns:m.04306rv ns:language.human_language.countries_spoken_in ?x .
?x ns:location.country.official_language ns:m.04306rv .
?x ns:location.location.contains ?c .
?c ns:aviation.airport.serves ns:m.01b98m . 
}