1. Cash back activities: Pinduoduo will launch cash back activities from time to time, but certain conditions must be met before it can be cashed back. For example, you need to invite friends to join the group, and you need to complete the spelling list within the specified time.

2. Punching activities: Pinduoduo will launch punching activities. Users need to open the Pinduoduo APP and log in every day, and they can get rewards after logging in for a certain number of days.

3. Free-of-order activities: Pinduoduo will launch free-of-order activities from time to time, but only when certain conditions are met can it be free. For example, you need to invite friends to join the group, and you need to complete the spelling list within the specified time.

4. Free pick-up activity: Pinduoduo will launch a free pick-up activity, and users need to invite friends to join the group and complete the task to get free goods.