With no explanation, label each line with "O", "art-broadcastprogram", "art-film", "art-music", "art-other", "art-painting", "art-writtenart", "building-airport", "building-hospital" or "building-hotel" preceded by ":".
This
was
achieved
by
using
a
one-way
valve
(
a
leather
or
rubber
flap
over
a
hole
in
the
crankcase
)
,
to
let
air
escape
the
crankcase
but
not
enter
it
.
This:O
was:O
achieved:O
by:O
using:O
a:O
one-way:O
valve:O
(:O
a:O
leather:O
or:O
rubber:O
flap:O
over:O
a:O
hole:O
in:O
the:O
crankcase:O
):O
,:O
to:O
let:O
air:O
escape:O
the:O
crankcase:O
but:O
not:O
enter:O
it:O
.:O