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 ":".
Before
that
ducklings
are
grey-brown
with
off-white
cheeks
and
underpart
.
Before:O
that:O
ducklings:O
are:O
grey-brown:O
with:O
off-white:O
cheeks:O
and:O
underpart:O
.:O