With no explanation, label each line with "O", "location-other", "art-broadcastprogram", "art-film", "art-music", "art-other", "art-painting", "art-writtenart", "building-airport" or "building-hospital" preceded by ":".
Although
dust
storms
in
the
Gobi
desert
have
occurred
from
time
to
time
throughout
history
,
they
became
a
pronounced
problem
in
the
second
half
of
the
20th
century
due
to
intensified
agricultural
pressure
and
desertification
.
Although:O
dust:O
storms:O
in:O
the:O
Gobi:location-other
desert:O
have:O
occurred:O
from:O
time:O
to:O
time:O
throughout:O
history:O
,:O
they:O
became:O
a:O
pronounced:O
problem:O
in:O
the:O
second:O
half:O
of:O
the:O
20th:O
century:O
due:O
to:O
intensified:O
agricultural:O
pressure:O
and:O
desertification:O
.:O