Question: Which currently working coach has coached the Baltimore Ravens?
Answer(s):
answer: John Harbaugh

SPARQL query:
#MANUAL SPARQL
PREFIX ns: <http://rdf.freebase.com/ns/>
SELECT DISTINCT ?x 
WHERE {
  {
    ns:m.01ct6 ns:american_football.football_team.current_head_coach ?x .
  }
  UNION
  {
    ns:m.01ct6 ns:sports.sports_team.coaches ?y .
	?y ns:sports.sports_team_coach_tenure.coach ?x .
	?y ns:sports.sports_team_coach_tenure.position ns:m.02y5kn . #coach
  }?x ns:people.person.profession ns:m.02y5kn . 
}