Everything is the teacher's kindness, and it's all my fault. I like science classes, not only because of the beauty of science, but also because of the teachers' earnest teaching. However, as a student determined to learn this course well, I not only failed the teacher's hard work, but also failed the teacher's trust in me. I didn't buy books, not because of the problem of more and less, but because I didn't take them seriously. In order to encourage me to answer more questions actively, please adopt me.