Question: What country is the Mekong River located in, and also has the Khmer language as an official language?
Answer(s):
answer: Cambodia

SPARQL query:
PREFIX ns: <http://rdf.freebase.com/ns/>
SELECT DISTINCT ?x
WHERE {
FILTER (?x != ns:m.0j0g5)
FILTER (!isLiteral(?x) OR lang(?x) = '' OR langMatches(lang(?x), 'en'))
ns:m.0j0g5 ns:location.location.partially_containedby ?x .
?x ns:location.country.official_language ns:m.01lqm . 
}