I heard that the teacher will ask you why you want to take the exam in our school.

This content is generally not fixed, some prepare a topic and then draw lots, and some interview teachers ask questions randomly according to the candidates' situation. Topics are generally very simple, related to daily life, life experience and learning experience. If your English is ok, you don't have to worry too much. If you feel uncertain, you can prepare yourself a familiar and interesting experience. No matter what topic you draw, you can always quote from it. For example, if you have lost weight, you can use this answer when you are asked about your life experiences and feelings. For example, your name comes from many sources, or you can prepare a related topic. Then ask any personal questions.