With no explanation, label each line with "O", "product-weapon", "art-broadcastprogram", "art-film", "art-music", "art-other", "art-painting", "art-writtenart", "building-airport" or "building-hospital" preceded by ":".
When
mounted
inside
a
tank
,
the
MG
34
also
lacked
a
butt-stock
.
When:O
mounted:O
inside:O
a:O
tank:O
,:O
the:O
MG:product-weapon
34:product-weapon
also:O
lacked:O
a:O
butt-stock:O
.:O