正则 与伪静态

Question

<RewriterRule>
        <LookFor>http://a.a.com/(\?)([\w\20%\w\+\/=]{1,})</LookFor>
        <SendTo><![CDATA[~/a.aspx?$2]]></SendTo>

</RewriterRule>

<RewriterRule>
        <LookFor>http://a.b.com/cc_(\d{1,})_(\d{1,})_(\d{1,})_((\d+)(,\d+)*)\.html</LookFor>
        <SendTo><![CDATA[~/bb.aspx?lid=$1&order=$2&page=$3&d_city=$4]]></SendTo>
      </RewriterRule>

可以帮忙讲解一下上面两条伪静态吗？ 主要是看不懂正则