@prefix bio: <http://purl.org/vocab/bio/0.1/> .
@prefix foaf: <http://xmlns.com/foaf/0.1/> .
@prefix time: <http://www.w3.org/2006/time#> .
@prefix ex: <http://example.org/ex#> .
@prefix thing: <http://example.org/thing#> .

thing:maria 
  a foaf:Person ;
  bio:condition thing:mariaUnmarried ;
  bio:condition thing:mariaMarried .

thing:mariaUnmarried 
  foaf:name "Maria Smith" ;
  time:start "1867" ;
  time:end "1888" .

thing:mariaMarried 
  foaf:name "Maria Johnson" ;
  time:start "1888" ;
  time:end "9999" .