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 ":".
The
prototype
was
flown
as
a
tri-motor
aircraft
in
the
initial
stages
of
the
test-flying
program
.
The:O
prototype:O
was:O
flown:O
as:O
a:O
tri-motor:O
aircraft:O
in:O
the:O
initial:O
stages:O
of:O
the:O
test-flying:O
program:O
.:O