The CET-4 oral test is divided into C and C+. According to the public information inquired, Grade C is to test students with weak English foundation and poor English expression ability; C+ level is a test for students with good English foundation and strong English expression ability. In the specific content of the exam, C+ level is more difficult than C level, and the language difficulty, complexity and scope of the exam are higher. In addition, the C+ level exam will also increase the content of listening and speaking and oral expression of body language. Therefore, C+ proficiency test can evaluate students' English level and oral expression ability more comprehensively.