machine_question: what was the name of the public speaker which spoke about Anti-Apartheid 's brothers
question: Who are the brothers of the anti-apartheid public speaker?
sparql: PREFIX ns: <http://rdf.freebase.com/ns/>
  SELECT DISTINCT ?x
  WHERE {
  FILTER (?x != ?c)
  FILTER (!isLiteral(?x) OR lang(?x) = '' OR langMatches(lang(?x), 'en'))
  ?c ns:event.public_speaker.speeches_or_presentations ?k .
  ?k ns:event.speech_or_presentation.speech_topic ns:m.04lxyz0 . 
  ?c ns:people.person.sibling_s ?y .
  ?y ns:people.sibling_relationship.sibling ?x .
  ?x ns:people.person.gender ns:m.05zppz .
  }
  
webqsp_question: what was the name of jfk 's brothers