With no explanation, label each line with "product-airplane", "O", "art-broadcastprogram", "art-film", "art-music", "art-other", "art-painting", "art-writtenart", "building-airport" or "building-hospital" preceded by ":".
Although
propeller-driven
,
the
KC-97s
were
significantly
faster
than
the
KB-29s
and
were
designed
for
aerial
refueling
.
Although:O
propeller-driven:O
,:O
the:O
KC-97s:product-airplane
were:O
significantly:O
faster:O
than:O
the:O
KB-29s:product-airplane
and:O
were:O
designed:O
for:O
aerial:O
refueling:O
.:O