I use asp.net to call a web service, and it return below

<ResponsePacket xmlns="urn:Microsoft.Search.Response">
    <Response domain="QDomain">
        <Copyright>Microsoft (c) Office SharePoint (tm) Portal Server 2003</Copyright>
        <Range>
            <StartAt>1</StartAt>
            <Count>1000</Count>
            <TotalAvailable>461</TotalAvailable>
            <Results>
                <Document type="" relevance="569" xmlns="urn:Microsoft.Search.Response.Document">
                    <Title>推荐需求</Title>
                    <Action>
                        <LinkUrl fileExt="aspx" size="0">http://sopapp03.sol.shuion.com.cn/C13/env/Lists/List1/view.aspx</LinkUrl>
                    </Action>
                    <Description>
                        1 上海动物园科普志愿者报名（需求开放中） 2006-03-09T06:39:48Z 2006-03-04T07:18:21Z Kevin Zhou Yun Peng 21 Kevin Zhou Yun Peng 6 -1 0 上海动物园科普志愿者报名（需求开放中） 上海动物园科普志愿者报名（需求开放中） 1 100.000000000000 {4ACF93A3-A5B5-4FEB-82A3-06C1B523726A} <div>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<font color="#000080" size=2>
                    </Description>
                    <Date>2008-04-14T02:31:29</Date>
                </Document>
                <Document type="" relevance="561" xmlns="urn:Microsoft.Search.Response.Document">
                    <Title>环境保护</Title>
                    <Action>
                        <LinkUrl size="55669">http://sopapp03.sol.shuion.com.cn/C13/env</LinkUrl>
                    </Action>
                    <Description>
                        帮助 瑞安门户网站  环境保护  当前位置 动作 项目介绍 环境保护已经日益成为我们所关注的话题,生存危机、可持续发展深入到我们每天的生活。瑞安海鸥社将通过一系列的环境保护活动推动我们身边的生活环境、工作环境、生态环境的改善。同时，我们也将组织志愿者参与我们的各项宣传、推广活动，推动社会的可持续发展。  想象一下天蓝草绿水清的世界，我们可以做得更多！  作者  2006-4-4 10:43 4月9日（星期日）上午9：00  大宁灵石公园正门                           2006-3-9 10:20 2006-3-9 14:39 走入绿色，发现亮色！
                    </Description>
                    <Date>2008-03-03T09:18:20</Date>
                </Document>
    </Results>
        </Range>
        <Status>SUCCESS</Status>
    </Response>
</ResponsePacket>

 The xml is utf-16 format, as web service is return xml format so I read it and I want its description

 string XMLresult=WebService.QueryResult();
  System.Xml.XmlDocument dc = new System.Xml.XmlDocument();
 dc.LoadXml(XMLresult);
   XmlNodeList nodes=dc.SelectNodes("/ResponsePacket/Response/Range/Results/Document");
   foreach (XmlNode node in nodes)
     {
         Response.Write(node["description"]);
     
     }

when I run, It always return nothing, I debug , find nodes count is 0.

if I open the xml in  vs2008, it give error say "the xml is not formatted",as 

  <Description> æˆ·ç½‘ç«™    您好 IT Portal 瑞安é </Description> contain  #x20 illegal character.

how to solve this problem

I don't know if your underlying data is corrupt, or it became corrupt when you pasted it into the web page but the XML was malformed with these unbalanced elements:

    <div>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<font color="#000080" size="2">

After deleting the above, I was able to select the Descriptions with this XPath query:

    //def:Description