Question: What instruments did the person who wrote "I Am the World" play?
Answer(s):
answer: Piano
answer: Violin

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:music.lyricist.lyrics_written ns:m.0_7vgyh . 
?c ns:music.group_member.instruments_played ?x .
}