what is the {start time} for {David Attenborough} has {member of} as {Royal Society} ?
SIR David Attenborough joined the Royal Society in which year?
when did David Attenborough become the member of the Royal Society?
SELECT ?n WHERE { ?e property:start_time ?n . ?e property:member_of resource:Royal_Society . resource:David_Attenborough property:member_of ?e }
select distinct ?value  where {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q183337> .
?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/Q123885> .
?statement <http://www.wikidata.org/entity/P580> ?value. 
} 

SELECT ?value WHERE { wd:Q183337 p:P463 ?s . ?s ps:P463 wd:Q123885 . ?s pq:P580 ?value}