<?xml version="1.0"?> 
<doc>
  <a>1<b>under1</b>1.5</a>
  <a>2<b>under2</b>2.5</a>
  <a>3<b>under3</b>3.5<b>under3.5</b>3.9</a>
  <a>4<c>under4</c>4.5<b>under4.5</b>4.9</a>
  <a>5<b>under5</b>5.5<x>under5.5</x>5.9</a>
  <a>6<b>under6</b>6.5<c>under6.5</c>6.9</a>
  <a>7<b>under7</b>7.5</a>
</doc>