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 <br>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 <br>, the collection and collation of data, and then 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.

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这篇毕业论文的时候，自己也从当年的一个的懵懂孩童变成了一个<br>成熟青年，回想自己的十几年的学习生涯，哭过，笑过，一路走下来也实属不容易。<br>在本论文的撰写过程中，非常感谢我的指导老师，自始至终得到牛老师的悉心指导，从本文的选题，到论文思路的引导、文字的组织、结构的安排<br>、资料的收集和整理，再到论文的修改，每一项都治学严谨，老师倾注了大量的心血，才得以是我顺利地完成本文的写作。

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 one<br>It's not easy for a mature youth to go down all the way after recalling his ten years of learning career, crying and laughing.<br>In the process of writing this paper, thank you very much to my instructor, 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, and the arrangement of the structure<br>, data collection and collation, and then to the revision of the thesis, each of them is rigorous, and the teacher has devoted a lot of effort to my writing.<br>