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 ":".
An
additional
seventh
unit
commissioned
in
April
1967
.
An:O
additional:O
seventh:O
unit:O
commissioned:O
in:O
April:O
1967:O
.:O