The gap is not big. The Second Test of the National Senior High School Mathematics League is a high-level mathematics competition in China's senior high school, and its status is much higher than that organized by the provinces themselves. About 400 students from all over the country who have achieved excellent results in this competition are eligible to participate in the China Mathematical Olympics (CMO) sponsored by the Chinese Mathematical Society. The college entrance examination consists of university professors, in-service teachers in high schools and subject teaching experts, among which the number of university professors accounts for the largest proportion. The proposition of the college entrance examination paper is a state secret, and the relevant departments of each province entrust the examination center of the Ministry of Education with full authority, and the personnel who participate in the college entrance examination proposition are strictly screened.