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 ":".
At
such
times
,
the
river
's
normally
narrow
path
could
expand
to
be
as
much
as
a
mile
wide
.
At:O
such:O
times:O
,:O
the:O
river:O
's:O
normally:O
narrow:O
path:O
could:O
expand:O
to:O
be:O
as:O
much:O
as:O
a:O
mile:O
wide:O
.:O