Synchronous classes and extended classes usually refer to the course remedial classes that students attend outside the school. These courses are designed to help students improve their academic performance and expand their knowledge. The difference between them lies in the different teaching contents and methods.

Synchronous classes mainly focus on the review and counseling of school courses. Its goal is to help students better understand and master the knowledge points in school textbooks and improve their academic performance in school classrooms. Synchronous classes usually teach according to the school's teaching progress and curriculum arrangement, focusing on strengthening the knowledge points, problem-solving methods and examination skills of school textbooks. The teaching content of synchronous classes corresponds to the school, helping students to keep up with the teaching progress of the school.

Outward bound classes pay more attention to deepening knowledge and expanding learning. The goal of the outreach class is to broaden students' knowledge and provide more extended knowledge and applied skills related to school textbooks. Outward bound training courses usually cover the knowledge fields outside the school curriculum in a more comprehensive way, helping students to build a deeper understanding and thinking ability. The teaching content and methods of extended classes are relatively flexible, and teachers will conduct more in-depth teaching according to students' interests and abilities.

To sum up, synchronous classes pay attention to the review and guidance of school courses to help students keep up with the teaching progress of the school; Outward bound training courses focus on in-depth knowledge and extended learning, providing a wider range of knowledge and learning ability. Students can choose their own courses according to their learning needs and goals.