Question: What countries border the country that uses Vietnamese dong?
Answer(s):
answer: Cambodia
answer: Laos
answer: China

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.currency_used ns:m.03ksl6 . 
?c ns:location.location.adjoin_s ?y .
?y ns:location.adjoining_relationship.adjoins ?x .
?x ns:common.topic.notable_types ns:m.01mp .
}