Very good. Learning and thinking level S is the best level, which is equivalent to 98 to 99 points. This is the evaluation system of teachers by learning and thinking: all teachers are divided into four grades: S, A, B, C and D from high to low. Xueersi Online School is an online education platform for primary and secondary schools under the NYSE listed companies, which provides extracurricular teaching for children aged 6 to 18.