Training institutions usually have to go through three levels to recruit teachers, namely interview, trial lecture and proficiency test. Proficiency test is a time-limited test to examine the speed, skills, methods, time and correct rate of teachers' problem solving. This level directly examines the true level of teachers. The trial lecture is to examine the teacher's lesson preparation level, lecture style, expression ability, blackboard writing level, teaching skills, classroom control ability and student management level through on-site trial lecture.