What is {twinned administrative body} of {Tver} that is {start time} is {1997-6-7} ?
Since July 6,1997, what is Tver's sister city?
What has been the sister city of Tver since July 6th, 1997?
SELECT ?l WHERE { resource:Tver property:twinned_administrative_body ?a . ?a property:start_time ?l . ?a property:twinned_administrative_body ?l . FILTER ( CONTAINS ( YEAR ( ?l ) , '1997' ) ) }
select distinct ?obj  where {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q2288> .
?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> ?obj .
?statement <http://www.wikidata.org/entity/P580> <1997-6-7>
} 

SELECT ?obj WHERE { wd:Q2288 p:P190 ?s . ?s ps:P190 ?obj . ?s pq:P580 ?x filter(contains(YEAR(?x),'1997')) }