According to the relevant information released by Wujiang District Primary School Education Bureau, the exam questions in Xiao Yang's class are as difficult as other classes, and there is no particularly difficult topic. Wujiang District Primary School Education Bureau has been committed to ensuring the fairness of education and ensuring that the teaching quality and examination difficulty of each class are relatively balanced. Therefore, it is not difficult to determine the topic of Xiao Yang class in Wujiang District Primary School.