key: a
key: aI
key: aa
key: aba
key: United States
key: United States of America
key: The United States
key: The United States of America
data: <k>a<opt>I</opt></k>
<k>a<opt>b</opt>a</k>
<k><opt>The</opt> United States <opt>of America</opt></k>
<dtrn><c>A</c></dtrn>