Introduction to the two-person stage: The two-person stage is a type of opera popular in the Inner Mongolia Autonomous Region and the northern parts of Shanxi, Shaanxi and Hebei provinces. It is commonly known as "double stuff", also known as "two-person class". Because most of its repertoire adopts the form of one ugly person and two people singing, it is called Errentai, which is also one of the local folk cultures.