With no explanation, label each line with "O", "other-chemicalthing", "art-broadcastprogram", "art-film", "art-music", "art-other", "art-painting", "art-writtenart", "building-airport" or "building-hospital" preceded by ":".
The
main
metabolic
mechanism
is
the
hydrolysis
of
an
acetamide
to
a
carboxylic
acid
.
The:O
main:O
metabolic:O
mechanism:O
is:O
the:O
hydrolysis:O
of:O
an:O
acetamide:other-chemicalthing
to:O
a:O
carboxylic:other-chemicalthing
acid:other-chemicalthing
.:O