不会正则表达式，这个比较常用，留用

注意group[0].value中带着两头筛选条件，group[1].value中没有

string str12="<a href=\"标注1\" target=_blank>标注2</a>";

            string pattern12 = "<a\\shref=\"([^\"]*)\"\\starget=_blank>(.*?)</a>";

            var m = Regex.Match(str12,pattern12,RegexOptions.Multiline | RegexOptions.Singleline | RegexOptions.IgnoreCase);

            string bs1 = m.Groups[1].Value;
            string bs2 = m.Groups[2].Value;


            string str3 = "<a class=bl href=\"profile.PHP?action=show&uid=85521\">标注3</a>";
            string pattern3 = "<a\\sclass=bl[^<]*>(.*?)</a>";


            m = Regex.Match(str3,pattern3,RegexOptions.Multiline | RegexOptions.Singleline | RegexOptions.IgnoreCase);

            string bs3 = m.Groups[1].Value;


            string str4 = "<div class=f10>标注4</div>";
            string pattern4 = "<div\\sclass=f10[^<]*>(.*?)</div>";


            m = Regex.Match(str4,pattern4,RegexOptions.Multiline | RegexOptions.Singleline | RegexOptions.IgnoreCase);

            string bs4 = m.Groups[1].Value;