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 ":".
Once
inside
the
gas
cylinder
,
propellant
gases
pass
through
an
L-shaped
channel
machined
in
the
piston
head
and
are
directed
forward
towards
the
gas
valve
.
Once:O
inside:O
the:O
gas:O
cylinder:O
,:O
propellant:O
gases:O
pass:O
through:O
an:O
L-shaped:O
channel:O
machined:O
in:O
the:O
piston:O
head:O
and:O
are:O
directed:O
forward:O
towards:O
the:O
gas:O
valve:O
.:O