Question: In the nation which has a capital of Doha, what type of currency is used?
Answer(s):
answer: Qatari riyal

SPARQL query:
PREFIX ns: <http://rdf.freebase.com/ns/>
SELECT DISTINCT ?x
WHERE {
FILTER (?x != ?c)
FILTER (!isLiteral(?x) OR lang(?x) = '' OR langMatches(lang(?x), 'en'))
?c ns:location.country.capital ns:m.0f2yw . 
?c ns:location.country.currency_used ?x .
}