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 ":".
Lewis
acid
catalysts
such
as
AlCl3
and
FeCl3
are
required
.
Lewis:other-chemicalthing
acid:other-chemicalthing
catalysts:other-chemicalthing
such:O
as:O
AlCl3:other-chemicalthing
and:O
FeCl3:other-chemicalthing
are:O
required:O
.:O