With no explanation, label each line with "O", "other-chemicalthing", "art-broadcastprogram", "art-film", "art-music", "art-other", "art-painting", "art-writtenart", "building-airport" or "building-hospital" preceded by ":".
It
has
a
metallic
luster
that
,
when
exposed
to
air
,
quickly
tarnishes
to
a
bluish-gray
tinge
,
resembling
lead
.
It:O
has:O
a:O
metallic:O
luster:O
that:O
,:O
when:O
exposed:O
to:O
air:O
,:O
quickly:O
tarnishes:O
to:O
a:O
bluish-gray:O
tinge:O
,:O
resembling:O
lead:other-chemicalthing
.:O