1. The logic of mathematics: The second day of junior high school is the starting point of mathematics education, and students mainly learn basic mathematical knowledge and concepts at this stage. Congruent trigonometric function is an advanced mathematical concept, which requires a deeper mathematical foundation and logical thinking ability. Senior two students may not have reached the level of understanding and using congruent trigonometric functions.

2. Consideration of teaching progress: Mathematics course has a certain teaching progress, and different concepts and principles are gradually introduced in a certain order. Congruent trigonometric function is the content of high school mathematics, which is often involved and explained in detail in high school mathematics courses. According to the syllabus and students' level, math teachers in Grade Two can choose to teach only the math knowledge points that suit them.

3. Consideration of study burden: Junior high school students usually need to study many subjects, including Chinese, math, English and science. If the concept of senior high school mathematics is introduced in the second grade, it will increase students' learning burden and pressure. The math teacher in Grade Two may want students to master the basic knowledge and thinking methods of mathematics first, so as to lay a solid foundation for further study in the future.

Generally speaking, the reason why the math teacher in Senior Two refuses to use congruent trigonometric function may be because of the students' math level and learning burden, as well as the reasonable arrangement of teaching progress. By gradually introducing and deepening mathematical concepts, students can better master mathematical knowledge and lay a solid foundation for future study.