光阴似箭，眨眼间，大学四年已经接近了尾声。当自己怀着忐忑不安的心情完成

In the blink of an eye, in the blink of an eye, four years of college has come to an end. When I finished this thesis with an uneasy feeling, I also changed from a ignorant child to a mature young man, recalling my ten years of study, crying, laughing, and walking down the road. It's not easy. <br>In the process of writing this paper, I am very grateful to my instructor. I have been carefully guided by Mr. Niu from the beginning to the end, from the topic selection of this article, to the guidance of the paper's ideas, the organization of the text, the arrangement of the structure, the collection and collation of data, To the revision of the thesis, every item is rigorously studied, and the teacher devoted a lot of effort, so that I can successfully complete the writing of this article.

The light is like an arrow, in the blink of an eye, the university four years has come to an end. When he completed this graduation thesis with a restless mood, he also from that year a understanding child into a mature young man, recall their ten years of study career, crying, laughing, all the way down is not easy.<br>In the writing process of this thesis, thank you very much for my guidance teacher, from beginning to end to get the careful guidance of the cow teacher, from the selection of this article, to the guidance of the paper ideas, the organization of the text, the organization of the structure, the collection and collation of information, to the revision of the paper, each one is rigorous, the teacher poured a lot of effort, i was able to successfully complete the writing of this article.

Time flies. In the blink of an eye, the four years of University have come to an end. When I finished this graduation thesis with uneasy mood, I also changed from an ignorant child to a mature youth. It's not easy to go down all the way when I think about my ten years of learning career, crying, laughing.<br>In the process of writing this paper, I am very grateful to my tutor, who has been carefully guided by Mr. Niu from the beginning to the end. From the topic selection of this paper, to the guidance of the ideas of the paper, the organization of the text, the arrangement of the structure, the collection and collation of the data, to the revision of the paper, each of them is rigorous in academic research, and the teacher has devoted a lot of effort to my success in writing this paper Do.