Question: The Kingdom of Prussia and England shared which political system?
Answer(s):
answer: Constitutional monarchy

SPARQL query:
PREFIX ns: <http://rdf.freebase.com/ns/>
SELECT DISTINCT ?x
WHERE {
FILTER (?x != ns:m.02jx1)
FILTER (!isLiteral(?x) OR lang(?x) = '' OR langMatches(lang(?x), 'en'))
ns:m.02jx1 ns:location.country.form_of_government ?x .
?x ns:government.form_of_government.countries ?c .
?c ns:type.object.name "Kingdom of Prussia"@en . 
}