what the differences between And

I try to understand the diffrence between these codes:

<!--[if (gt IE 9)|!(IE)]> <p>a</p> <![endif]-->
<!--[if (gt IE 9)|!(IE)]><!--> <p>b</p> <!--<![endif]-->
<!--[if lte IE 9]> <p>c</p> <![endif]-->
<!--[if lte IE 9]><!--> <p>d</p> <!--><![endif]-->

What the meaning of the <!--> after the <!--[if (gt IE 9)|!(IE)]>? and what is the differences between the lines, when I run it on my web i can only see "b" and "d"