With no explanation, label each line with "O", "other-astronomything", "art-broadcastprogram", "art-film", "art-music", "art-other", "art-painting", "art-writtenart", "building-airport" or "building-hospital" preceded by ":".
The
Horsehead
Nebula
(
also
known
as
Barnard
33
)
is
a
small
dark
nebula
in
the
constellation
Orion
.
The:O
Horsehead:other-astronomything
Nebula:other-astronomything
(:O
also:O
known:O
as:O
Barnard:other-astronomything
33:other-astronomything
):O
is:O
a:O
small:O
dark:O
nebula:O
in:O
the:O
constellation:O
Orion:other-astronomything
.:O