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
maiden
flight
of
the
Hs
127
V1
was
at
the
end
of
1937
.
The:O
maiden:O
flight:O
of:O
the:O
Hs:product-airplane
127:product-airplane
V1:product-airplane
was:O
at:O
the:O
end:O
of:O
1937:O
.:O