With no explanation, label each line with "O", "art-broadcastprogram", "art-film", "art-music", "art-other", "art-painting", "art-writtenart", "building-airport", "building-hospital" or "building-hotel" preceded by ":".
They
sold
it
and
its
50
slaves
to
a
relative
.
They:O
sold:O
it:O
and:O
its:O
50:O
slaves:O
to:O
a:O
relative:O
.:O