*--------------------------------------------------------------------------------------------*
| 5 3 2| 7 1 9| 6 8 4|
| 7 6 1| 4 8 5| 2 9 3|
| 9 4 8| 3 2 6| 7 5 1|
|------------------------------+------------------------------+------------------------------|
| 6 1 3| 2 9 7| 5 4 8|
| 2 8 9| 6 5 4| 3 1 7|
| 4 7 5| 8 3 1| 9 2 6|
|------------------------------+------------------------------+------------------------------|
| 8 2 4| 9 7 3| 1 6 5|
| 3 5 6| 1 4 2| 8 7 9|
| 1 9 7| 5 6 8| 4 3 2|
*--------------------------------------------------------------------------------------------*
在8列有一显性4数对1234,既可得B8=9