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 ":".
The
design
of
the
recoil
spring
and
bolt
was
the
most
controversial
and
influential
aspect
of
the
M.K
.
The:O
design:O
of:O
the:O
recoil:O
spring:O
and:O
bolt:O
was:O
the:O
most:O
controversial:O
and:O
influential:O
aspect:O
of:O
the:O
M.K:O
.:O