请教正则表达式问题

HTML code

<tr>            <td align="center" class="subboxrb">                5.00            </td>            <td align="center" class="subboxrb">                正常            </td>            <td align="center" class="subboxrb">                20121231000000            </td>        </tr>

我想取出5.00这个值，我的代码如下

C# code

string content = System.Web.HttpUtility.HtmlDecode(reader.ReadToEnd());            string strBalance = "";            string strBalanceLeft = "<td align=\"center\" class=\"subboxrb\">";            string strBalanceRight = "</td>";            string strBalanceReguelar = strBalanceLeft + "(.*?)" + strBalanceRight;            MatchCollection collBalance = Regex.Matches(content, strBalanceReguelar);            if (collBalance != null && collBalance.Count != 0)            {                strBalance = collBalance[0].Value;                strBalance = strBalance.Replace(strBalanceLeft, "");                strBalance = strBalance.Replace(strBalanceRight, "");            }

但是匹配不到，不知什么原因，请指点，谢谢

[解决办法]
因为你没有匹配换行符号

C# code

 string strBalanceReguelar = strBalanceLeft + @"\s*(.*?)\s*" + strBalanceRight;