With no explanation, label each line with "location-GPE", "O", "art-broadcastprogram", "art-film", "art-music", "art-other", "art-painting", "art-writtenart", "building-airport" or "building-hospital" preceded by ":".
The
defences
had
been
strengthened
since
the
British
had
left
the
islands
.
The:O
defences:O
had:O
been:O
strengthened:O
since:O
the:O
British:location-GPE
had:O
left:O
the:O
islands:O
.:O