"I watch TV and go shopping on weekends."
Correction to my previous guess.
The way the grammar works for this. It is joining multiple actions together.
You do his by convertion of the action words (verbs) to plain past tense (見る→見た) and add り. At the end of the action word list you have some tense form of する. The form of (する/した/します etc) controls to tense of all other joined together actions. The り joining form is for incomplete lists.