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 ":".
Once
there
,
they
then
made
a
rubbing
of
the
clue
onto
a
piece
of
paper
.
Once:O
there:O
,:O
they:O
then:O
made:O
a:O
rubbing:O
of:O
the:O
clue:O
onto:O
a:O
piece:O
of:O
paper:O
.:O