Точнее так:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
<title>Без имени</title>
<meta http-equiv="content-type" content="text/html;charset=utf-8" />
<meta name="generator" content="Geany 0.17" />
</head>
<style type="text/css">
fieldset { width: 20em; height: 20 em }
.left { float:left; }
.right { float: right; }
.left .item { border: 1px solid green; margin: 5px; }
.right .item { border: 1px solid red; margin: 5px; }
.clear { clear:both; }
</style>
<body>
<fieldset>
<legend>test</legend>
<div class="left">
<div class="item">test 1</div>
<div class="item">test 2</div>
<div class="item">test 3</div>
<div class="item">test 4</div>
<div class="item">test 5</div>
</div>
<div class="right">
<div class="item">test 1</div>
<div class="item">test 2</div>
</div>
</fieldset>
</body>
</html>