what is the {start time} for {Armenia} has {member of} as {World Trade Organization} ?
When did Armenia join the World Trade Organization?
When did Armenia become a member of the World Trade Organization?
SELECT ?r WHERE { ?d property:member_of resource:World_Trade_Organization . resource:Armenia property:member_of ?d . ?d property:start_time ?r }
select distinct ?value  where {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q399> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P463> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> <http://wikidata.dbpedia.org/resource/Q7825> .
?statement <http://www.wikidata.org/entity/P580> ?value. 
} 

SELECT ?value WHERE { wd:Q399 p:P463 ?s . ?s ps:P463 wd:Q7825 . ?s pq:P580 ?value}