With no explanation, label each line with "O", "event-attack/battle/war/militaryconflict", "art-broadcastprogram", "art-film", "art-music", "art-other", "art-painting", "art-writtenart", "building-airport" or "building-hospital" preceded by ":".
The
war
followed
on
from
the
First
Opium
War
.
The:O
war:O
followed:O
on:O
from:O
the:O
First:event-attack/battle/war/militaryconflict
Opium:event-attack/battle/war/militaryconflict
War:event-attack/battle/war/militaryconflict
.:O