<html>
<style>
a:link,a:visited { color: #000;text-decoration: none;}
a:hover {text-decoration: underline;}
a.b:link,a.b:visited { color: #f00;text-decoration: none;}
a.b:hover {text-decoration: underline;}
</style>
<a href="#" class="b">aaa</a>
<a href="#">aaa</a>
</html>
至少应该这么写的，
