With no explanation, label each line with "O", "other-biologything", "art-broadcastprogram", "art-film", "art-music", "art-other", "art-painting", "art-writtenart", "building-airport" or "building-hospital" preceded by ":".
The
chemical
phosphorus
removal
in
those
systems
may
be
used
as
a
backup
system
,
for
use
when
the
biological
phosphorus
removal
is
not
removing
enough
phosphorus
,
or
may
be
used
continuously
.
The:O
chemical:O
phosphorus:other-biologything
removal:O
in:O
those:O
systems:O
may:O
be:O
used:O
as:O
a:O
backup:O
system:O
,:O
for:O
use:O
when:O
the:O
biological:O
phosphorus:other-biologything
removal:O
is:O
not:O
removing:O
enough:O
phosphorus:other-biologything
,:O
or:O
may:O
be:O
used:O
continuously:O
.:O