With no explanation, label each line with "O", "location-road/railway/highway/transit", "art-broadcastprogram", "art-film", "art-music", "art-other", "art-painting", "art-writtenart", "building-airport" or "building-hospital" preceded by ":".
Construction
of
this
line
was
necessary
before
the
Enz
Valley
Railway
and
the
Nagold
Valley
Railway
could
be
built
.
Construction:O
of:O
this:O
line:O
was:O
necessary:O
before:O
the:O
Enz:location-road/railway/highway/transit
Valley:location-road/railway/highway/transit
Railway:location-road/railway/highway/transit
and:O
the:O
Nagold:location-road/railway/highway/transit
Valley:location-road/railway/highway/transit
Railway:location-road/railway/highway/transit
could:O
be:O
built:O
.:O