Question: What instrument was played by the actor of "The Seville Concert: John Williams"?
Answer(s):
answer: Guitar

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:film.actor.film ?k .
?k ns:film.performance.film ns:m.0cs1w0g . 
?c ns:music.group_member.instruments_played ?x .
}