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 ":".
Their
marriage
lasted
until
his
death
in
April
1997
.
Their:O
marriage:O
lasted:O
until:O
his:O
death:O
in:O
April:O
1997:O
.:O