With no explanation, label each line with "O", "organization-other", "art-broadcastprogram", "art-film", "art-music", "art-other", "art-painting", "art-writtenart", "building-airport" or "building-hospital" preceded by ":".
They
were
the
prototype
electric
units
tested
by
the
District
Railway
.
They:O
were:O
the:O
prototype:O
electric:O
units:O
tested:O
by:O
the:O
District:organization-other
Railway:organization-other
.:O