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
school
was
enlarged
in
1912
and
again
in
1999
.
The:O
school:O
was:O
enlarged:O
in:O
1912:O
and:O
again:O
in:O
1999:O
.:O