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 ":".
Attempts
to
improve
it
have
been
undertaken
many
times
,
but
have
not
led
to
success
.
Attempts:O
to:O
improve:O
it:O
have:O
been:O
undertaken:O
many:O
times:O
,:O
but:O
have:O
not:O
led:O
to:O
success:O
.:O