重点是先抓取<td>里的内容，其它的就好说了:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;
using System.Text.RegularExpressions;

namespace ReadFile
{
    class Program
    {
        static void Main(string[] args)
        {
            string FilePath = @"E:\vs\bd.txt";
            StreamReader sr = new StreamReader(FilePath,Encoding.GetEncoding("UTF-8"));
            string FileContent = sr.ReadToEnd();
            FileContent = Regex.Replace(FileContent,"[\r\n\t]+","");
            string PatternTable = "(?i)<table class=\"result\"[^>]*?>(?:(?!</?table>)[\\s\\S])*?</table>";
            string PatternBlock = "<td class=\"c-default\" >(?:(?!</?td>)[\\s\\S])*?</td>";
            MatchCollection mc = Regex.Matches(FileContent,PatternBlock,RegexOptions.Multiline);
            Match mm = Regex.Match(FileContent,RegexOptions.Multiline);
            //Debug.WriteLine(mm.Groups.Count);
            foreach (Match mat in mc)
            {
                Console.WriteLine("================================================");
                Console.WriteLine(mat.Value);
            }

            Console.Read();
        }
    }
}