string tempStr = File.ReadAllText(@"C:\Documents and Settings\Administrator\桌面\Test.txt", Encoding.GetEncoding("GB2312"));//读取tx
                string pattern = @"(?i)(?<=\d+\s+)((\d+\s+){4})(\d+\s+\d+\.\d+\s*?(-?\d+\.[^+-]+?[+-]\d{2,}\s*?){4})(-?\d+\.[^+-]+?[+-]\d{2,})(?=\s)";
               
                //替换
                string begin_red = "<font color='Red'>";
                string end_red = "</font>";
                tempStr = Regex.Replace(tempStr, pattern, begin_red + "$1" + end_red + "$3" + begin_red + "$5" + end_red);
                /*
                 1 <font color='Red'>12 9 17 22 </font>0 0.0 2.342900261283D-04
                  1.500000000000D+01 2.828125000000D+01
                  5.904180000000D+05 <font color='Red'>2.000000000000D+00</font>
                 2 <font color='Red'>12 3 18 4 </font>0 0.0 3.832229413092D-04
                  2.000000000000D+00 0.000000000000D+00
                  7.218000000000D+03 <font color='Red'>3.000000000000D+00</font>
                 3 <font color='Red'>12 3 18 12 </font>0 0.0 2.402812242508D-05
                  4.300000000000D+01-8.521875000000D+01
                  3.847200000000D+04 <font color='Red'>2.000000000000D+00</font>
                 4 <font color='Red'>09 3 18 4 </font>0 0.0 1.261560246348D-04
                  7.400000000000D+01 3.546875000000D+01
                  7.218000000000D+03 <font color='Red'>3.000000000000D+00</font>
                 9 <font color='Red'>12 3 16 10 </font>0 0.0 1.455144956708D-04
                  3.600000000000D+01 7.240625000000D+01
                  2.881800000000D+04 <font color='Red'>4.000000000000D+00</font>
                10 <font color='Red'>12 3 18 4 </font>0 0.0-3.260467201471D-05
                  7.200000000000D+01 1.062500000000D+00
                  7.218000000000D+03 <font color='Red'>5.000000000000D+00</font>
                51 <font color='Red'>12 3 17 22 </font>0 0.0-2.426193095744D-04