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 ":".
Surgical
treatments
,
such
as
the
removal
of
ovaries
,
might
cause
periods
to
stop
altogether
.
Surgical:O
treatments:O
,:O
such:O
as:O
the:O
removal:O
of:O
ovaries:O
,:O
might:O
cause:O
periods:O
to:O
stop:O
altogether:O
.:O