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 ":".
This
is
the
first
case
of
gene
therapy
being
used
``
in
vivo
''
in
humans
.
This:O
is:O
the:O
first:O
case:O
of:O
gene:O
therapy:O
being:O
used:O
``:O
in:O
vivo:O
'':O
in:O
humans:O
.:O