1. Open the WPS table and create a new one. 2. Enter the classification in cell A 1, and enter the primary classification, secondary classification and tertiary classification in cells B 1, C 1 and D 1. Then select cells B 1, C 1 and D 1. 3. Click Data → Data Validity → Settings, select Allow → drop-down menu, and enter a list of "Primary Classification" in the source column, such as "Fruit, Vegetable and Meat". 4. Click OK, select cell B2 again, click Data → Data Validity → Settings again, select the drop-down menu, and enter "= indirect(substitute $ a2," _ "\ u0026" in the source column! $A$2:$A$4 ") and replace" $A$2:$A$4 "with the corresponding" first-class classification "range. 5. Click OK, select C2 cell again, click Data → Data Validity → Settings again, select the drop-down menu, and enter "= indirect(substitute $ A2," _ "\ u0026" in the source column! B "\ u0026 row (), true) ",and replace" b "with the corresponding" secondary classification "range. 6. Click OK, select the D2 cell again, click Data → Data Validity → Settings again, select the drop-down menu, and enter "= indirect(substitute $ A2," _ "\ u0026" in the source column! B "\ u0026 row (), true) ",and replace" b "with the corresponding" three-level classification "range. 7. Enter the first set of data in B2, C2 and D2, then copy cells B2, C2 and D2, and paste the copied data into the following cells. 8. Select cells B2, C2 and D2, click Format Brush in turn → select the cells to which the format needs to be applied, and apply the format. 9. You can then select the classification in column A, and then select the corresponding first, second and third-level classification in columns B, C and D. ..