With no explanation, label each line with "other-disease", "O", "art-broadcastprogram", "art-film", "art-music", "art-other", "art-painting", "art-writtenart", "building-airport" or "building-hospital" preceded by ":".
While
in
some
individuals
gingivitis
never
progresses
to
periodontitis
,
periodontitis
is
always
preceded
by
gingivitis
.
While:O
in:O
some:O
individuals:O
gingivitis:other-disease
never:O
progresses:O
to:O
periodontitis:other-disease
,:O
periodontitis:other-disease
is:O
always:O
preceded:O
by:O
gingivitis:other-disease
.:O