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 ":".
The
ballroom
had
opened
shortly
before
this
.
The:O
ballroom:O
had:O
opened:O
shortly:O
before:O
this:O
.:O