Question: When did John von Neumann take Kara Dan von Neumann as his spouse?
Paraphrase: When did John von Neumann and Kara Dan von Neumann get married?
SPARQL (Wikidata): SELECT ?value WHERE { wd:Q17455 p:P26 ?s . ?s ps:P26 wd:Q14100 . ?s pq:P580 ?value}