Acknowledgments  My thesis writing starts from March 2 and it is finished in June. The process of my writing is relatively smooth. Difficulties and frustrations occur from time to time, but I have been through them all with the help of following people. I want to extend my heartfelt thanks for their help.31045
First, I am grateful to my supervisor,, for his constant guidance and encouragement. At the beginning, I do not know how to set the thesis topic. And then in the process of my writing, I do not know how to collect relative information on the internet or in the book. At that time, I find it  impossible for me to complete my thesis. However, my tutor tells me how to narrow down my topic and how to collect information through the Internet and books. Under his patient and careful guidance, I have got a clear idea of writing thesis and then start to outline the frame of my thesis. The thesis can not be completed without his guidance and help.
Second, I would like to show my gratitude to all teachers who taught me during my two years’ college life, especially Zhong Ling, my Advanced English teacher. Her encyclopedic knowledge got me interested in the Western culture. She also teaches me how to use easier way to learn English. In fact, learning English should not be a daunting task.
I am willing to express my gratitude to my classmates and friends who always encourage me and give me some useful suggestions after reading my thesis.
Last, I will give my thanks to my parents who always support me and take care of me. Under their careful guidance, I am old enough to look after myself and them now.
Abstract
With the development of the society, the pace of life in metropolis speeds up, which puts anyone who lives there under great pressure both physically and mentally in terms of work, study and life. People start to find different ways to relax themselves and relieve stress brought about by work and study. Resorting to humor has become the best way to relax themselves.

In fact, humor can be manifested in many different forms. It can be shown in jokes in books which is called humorous stories. You can find it in TV series which is called situation comedy. It can also be shown in terms of body language, such as Chaplin, one of the most well-known actors who interprets humor with abundant animated actions.

While they are enjoying the funny stories and TV shows, few people were trying to figure out the reason why the conversation and action can produce humorous effect which could amuse the audience. In order to help them to improve the ability of appreciation of humor and become an intercultural person who knows humor and also can produce humor, this essay will give a pragmatic study of conversational humor based on the famous American situation comedy Two Broke Girls with the help of the rules of Politeness Principle by Leech. Then, it is necessary to analyze the reason why the conversations in this TV series could produce humorous effect.
This paper falls into six parts. The first part serves as an introduction. The second and third part aim at analyzing the humor and introducing the cooperative principle and politeness principle. The fourth part introduces that what is sitcom and analyzes the conversational humor in Two Broke Girls from politeness principle. The fifth part provides a better understanding of humor knowledge for the Chinese audience to watch American sitcoms. The sixth part functions as a conclusion.
Key Words: conversational humor, politeness principle, situation comedy
 摘要随着社会的发展，大城市的生活节奏越来越快，工作、学习、生活的压力有时让人疲惫不堪。在工作、学习之余，人们开始寻找各种方式来放松自己，缓解压力。其中，具有幽默元素的事物最受大家欢迎。
    其实幽默的表现形式很多，它可以表现在书本的段子中，称为幽默段子，它同样可以表现在电视剧中称为情景喜剧，当然它也可以表现在无声的舞台剧中，就像卓别林，他用丰富的肢体动作来展现幽默。 从语用学角度分析美国情景喜剧《破产姐妹》会话幽默:http://www.youerw.com/yingyu/lunwen_27068.html