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
the
time
of
its
construction
,
nothing
of
such
scale
had
ever
been
attempted
.
At:O
the:O
time:O
of:O
its:O
construction:O
,:O
nothing:O
of:O
such:O
scale:O
had:O
ever:O
been:O
attempted:O
.:O