what is the {start time} for {Plácido Domingo} has {spouse} as {Marta Domingo} ?
When was Placido Domingo Marta Domingo's husband?
When was Placido Domingo the spouse of Marta Domingo?
SELECT ?i WHERE { resource:Plácido_Domingo property:spouse ?o . ?o property:spouse resource:Marta_Domingo . ?o property:start_time ?i }
select distinct ?value  where {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q130853> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P26> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> <http://wikidata.dbpedia.org/resource/Q18206431> .
?statement <http://www.wikidata.org/entity/P580> ?value. 
} 

SELECT ?value WHERE { wd:Q130853 p:P26 ?s . ?s ps:P26 wd:Q18206431 . ?s pq:P580 ?value}