Question: Who is the current wife of the artist who had a concert tour named The Paul McCartney World Tour?
Answer(s):
answer: Nancy Shevell

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.artist.concert_tours ns:m.03h2b9f . 
?c ns:people.person.spouse_s ?y .
?y ns:people.marriage.spouse ?x .
?y ns:people.marriage.type_of_union ns:m.04ztj .
FILTER(NOT EXISTS {?y ns:people.marriage.from ?sk0} || 
EXISTS {?y ns:people.marriage.from ?sk1 . 
FILTER(xsd:datetime(?sk1) <= "2015-08-10"^^xsd:dateTime) })
FILTER(NOT EXISTS {?y ns:people.marriage.to ?sk2} || 
EXISTS {?y ns:people.marriage.to ?sk3 . 
FILTER(xsd:datetime(?sk3) >= "2015-08-10"^^xsd:dateTime) })
}