With no explanation, label each line with "O", "location-island", "art-broadcastprogram", "art-film", "art-music", "art-other", "art-painting", "art-writtenart", "building-airport" or "building-hospital" preceded by ":".
From
the
1950s
through
the
1970s
,
forests
on
Kruzof
Island
were
the
source
for
clearcut
timber
extraction
.
From:O
the:O
1950s:O
through:O
the:O
1970s:O
,:O
forests:O
on:O
Kruzof:location-island
Island:location-island
were:O
the:O
source:O
for:O
clearcut:O
timber:O
extraction:O
.:O