With no explanation, label each line with "product-airplane", "O", "art-broadcastprogram", "art-film", "art-music", "art-other", "art-painting", "art-writtenart", "building-airport" or "building-hospital" preceded by ":".
The
airfield
was
also
used
until
the
end
of
the
war
as
an
operational
training
airfield
for
North
American
P-51
Mustang
pilots
.
The:O
airfield:O
was:O
also:O
used:O
until:O
the:O
end:O
of:O
the:O
war:O
as:O
an:O
operational:O
training:O
airfield:O
for:O
North:product-airplane
American:product-airplane
P-51:product-airplane
Mustang:product-airplane
pilots:O
.:O