Question: Which of Mary Shelley's parents passed away firsts?
Answer(s):
answer: Mary Wollstonecraft

SPARQL query:
PREFIX ns: <http://rdf.freebase.com/ns/>
SELECT DISTINCT ?x
WHERE {
FILTER (?x != ns:m.04_by)
FILTER (!isLiteral(?x) OR lang(?x) = '' OR langMatches(lang(?x), 'en'))
ns:m.04_by ns:people.person.parents ?x .
?x ns:people.deceased_person.date_of_death ?num .
}
ORDER BY ?num LIMIT 1