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 ":".
It
became
diseased
after
it
was
struck
by
lightning
,
so
in
1925
the
middle
of
the
tree
was
excised
to
keep
the
remainder
healthy
.
It:O
became:O
diseased:O
after:O
it:O
was:O
struck:O
by:O
lightning:O
,:O
so:O
in:O
1925:O
the:O
middle:O
of:O
the:O
tree:O
was:O
excised:O
to:O
keep:O
the:O
remainder:O
healthy:O
.:O