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 ":".
Military
strategists
often
put
the
weapon
to
good
use
during
naval
battles
,
and
the
ingredients
to
its
construction
``
remained
a
closely
guarded
military
secret
''
.
Military:O
strategists:O
often:O
put:O
the:O
weapon:O
to:O
good:O
use:O
during:O
naval:O
battles:O
,:O
and:O
the:O
ingredients:O
to:O
its:O
construction:O
``:O
remained:O
a:O
closely:O
guarded:O
military:O
secret:O
'':O
.:O