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 ":".
They
reproduce
within
the
intestinal
epithelial
cells
.
They:O
reproduce:O
within:O
the:O
intestinal:O
epithelial:O
cells:O
.:O