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 ":".
Prior
to
the
closure
of
the
airline
,
several
network
expansions
were
planned
.
Prior:O
to:O
the:O
closure:O
of:O
the:O
airline:O
,:O
several:O
network:O
expansions:O
were:O
planned:O
.:O