With no explanation, label each line with "O", "person-athlete", "art-broadcastprogram", "art-film", "art-music", "art-other", "art-painting", "art-writtenart", "building-airport" or "building-hospital" preceded by ":".
On
25
September
2008
,
Roberts
announced
that
he
was
retiring
from
professional
football
after
he
failed
to
recover
from
the
knee
injury
,
with
an
attempted
surgery
being
unsuccessful
.
On:O
25:O
September:O
2008:O
,:O
Roberts:person-athlete
announced:O
that:O
he:O
was:O
retiring:O
from:O
professional:O
football:O
after:O
he:O
failed:O
to:O
recover:O
from:O
the:O
knee:O
injury:O
,:O
with:O
an:O
attempted:O
surgery:O
being:O
unsuccessful:O
.:O