Four years of study and life are coming to an end in this season, but my life is just a comma, and I will face the beginning of another journey. With the strong support of teachers, relatives and friends, I have worked hard for three years, but I have also gained a lot. When the thesis is about to go to Fu Zi, I am full of thoughts and can't be calm for a long time. The thesis was completed under the careful guidance of Mr. XXX, the tutor. From the topic selection to the final completion of the thesis, teacher XXX has been giving careful guidance and unremitting support. I am not your best student, but you are my most respected teacher. Your rigorous academic attitude, profound knowledge, profound thoughts and broad horizons have created a good spiritual atmosphere for me. It is better to teach people to fish than to teach them to fish. Being in it and deeply influenced by it, I not only accepted brand-new ideas, set up grand academic goals, but also understood the basic way of thinking. From the topic selection to the writing guidance, through your careful guidance and understanding after thinking, I often feel that "there is no doubt in the mountains and rivers, and there is a village."

I would also like to thank my parents, who not only cultivated my strong interest in learning, but also gave me pious shelter during my long life journey, and also provided great support and help for me to successfully complete my graduation thesis. In the future, I will study and work harder and live up to my parents' high expectations! I will respect and repay them!

At the same time, I also thank the college for providing me with a good graduation thesis environment.

Finally, I would like to thank all my mentors, friends and classmates who helped me in my graduation project, as well as the authors of the works I quoted or referred to in my design.