"Where did you go yesterday?" is the English translation of "你昨天去哪儿了". This question is often asked to inquire about someone's whereabouts or activities on a specific day in the past. It is a common way to catch up with friends or family and stay informed about each other's lives. In addition to asking about physical locations, this question can also be used to ask about plans or events that took place during the previous day. Overall, it is a simple yet useful question that allows people to connect and stay connected with one another.