With no explanation, label each line with "O", "person-politician", "person-other", "art-broadcastprogram", "art-film", "art-music", "art-other", "art-painting", "art-writtenart" or "building-airport" preceded by ":".
It
is
the
fourth
volume
of
Roberts
's
SPQR
series
,
featuring
Senator
Decius
Metellus
.
It:O
is:O
the:O
fourth:O
volume:O
of:O
Roberts:person-other
's:O
SPQR:O
series:O
,:O
featuring:O
Senator:O
Decius:person-politician
Metellus:person-politician
.:O