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
been
known
since
the
1980s
that
buprenorphine
binds
to
at
high
affinity
and
antagonizes
the
KOR
.
It:O
has:O
been:O
known:O
since:O
the:O
1980s:O
that:O
buprenorphine:other-chemicalthing
binds:O
to:O
at:O
high:O
affinity:O
and:O
antagonizes:O
the:O
KOR:other-chemicalthing
.:O