what is the {start time} for {Aarhus} has {twinned administrative body} as {Rostock} ?
When did Aarhus serve as a Rostock administrator?
What time did Aarhus serve as an adminstrative body at Rostock?
SELECT ?n WHERE { resource:Aarhus property:twinned_administrative_body ?y . ?y property:twinned_administrative_body resource:Rostock . ?y property:start_time ?n }
select distinct ?value  where {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q25319> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P190> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> <http://wikidata.dbpedia.org/resource/Q2861> .
?statement <http://www.wikidata.org/entity/P580> ?value. 
} 

SELECT ?value WHERE { wd:Q25319 p:P190 ?s . ?s ps:P190 wd:Q2861 . ?s pq:P580 ?value}