Question: What film was directed by Chad Stevens and features Zac Efron as an actor?
Answer(s):
answer: Melinda's World

SPARQL query:
PREFIX ns: <http://rdf.freebase.com/ns/>
SELECT DISTINCT ?x
WHERE {
FILTER (?x != ns:m.06wm0z)
FILTER (!isLiteral(?x) OR lang(?x) = '' OR langMatches(lang(?x), 'en'))
ns:m.06wm0z ns:film.actor.film ?y .
?y ns:film.performance.film ?x .
?x ns:film.film.film_casting_director ns:m.010z4ktm . 
}