MatchCollection ma = Regex.Matches(contt, @"([_]+\d+[_]+)|([_]+【小题\d+】[_]*)|(</u>【小题\d+】)", RegexOptions.Singleline | RegexOptions.Multiline | RegexOptions.IgnoreCase); var build = new StringBuilder(); int bs = 0; foreach (Match item in ma) { build.Append(item.Groups[0].ToString() + "^"); bs++; }