Specific methods: 1, male and female groups.

2. Same-sex combination.

3. Group by height: the short ones are in front and the tall ones are in the back.

4. Single and double grouping: report after random arrangement, with odd numbers as a group and even numbers as a group.

5. Grouping by array: report after random arrangement, such as 12345, 12345. Then the same number is reported as a group.

6. Group by student number.