| 摘要 | 第4-6页 |
| Abstract | 第6-7页 |
| Chapter 1 Introduction | 第11-16页 |
| 1.1 Background of the Study | 第11-14页 |
| 1.2 Significance of the Study | 第14页 |
| 1.3 Organization of the Thesis | 第14-16页 |
| Chapter 2 Literature Review | 第16-39页 |
| 2.1 An Overview of Lexical Chunks | 第16-29页 |
| 2.1.1 Research History of Lexical Chunks | 第16-22页 |
| 2.1.2 Definitions of Lexical Chunks | 第22-25页 |
| 2.1.3 Classifications of Lexical Chunks | 第25-29页 |
| 2.2 An Introduction to Business English Letters | 第29-33页 |
| 2.2.1 Classifications of Business English Letters | 第29-30页 |
| 2.2.2 Functions of Business English Letters | 第30-31页 |
| 2.2.3 Principles of Business English letters Writing | 第31-33页 |
| 2.3 Researches on Lexical Chunks in Business English Letters | 第33-34页 |
| 2.4 Theoretical Framework of the Study | 第34-39页 |
| 2.4.1 Classification of Lexical Chunks by Nattinger & DeCarrico | 第34-37页 |
| 2.4.2 Speech Act Theory by Leech | 第37-39页 |
| Chapter 3 Methodology | 第39-45页 |
| 3.1 Research Questions | 第39页 |
| 3.2 Sample Selection | 第39-43页 |
| 3.3 Analysis Procedures | 第43-45页 |
| Chapter 4 Results and Discussion | 第45-71页 |
| 4.1 Results of Sample Analysis | 第45-50页 |
| 4.2 Features in the Use of Lexical Chunks in Four Types of Business English Letters | 第50-57页 |
| 4.2.1 Polywords | 第50-51页 |
| 4.2.2 Phrasal Constraints | 第51-52页 |
| 4.2.3 Sentence Builders | 第52-55页 |
| 4.2.4 Summary | 第55-57页 |
| 4.3 Functions of Lexical Chunks in Business English Letters | 第57-63页 |
| 4.3.1 Achieving Native-like Fluency in Writing Business English Letters | 第57-59页 |
| 4.3.2 Enhancing Politeness of Business English Letters | 第59-62页 |
| 4.3.3 Increasing Flexibility of Business English Letters | 第62-63页 |
| 4.4 Lexical Chunks and Writing Principles of Business English Letters | 第63-68页 |
| 4.5 Implications of the Study | 第68-71页 |
| 4.5.1 Implications for Teachers | 第68-70页 |
| 4.5.2 Implications for Students | 第70-71页 |
| Chapter 5 Conclusion | 第71-74页 |
| 5.1 Major Findings | 第71-72页 |
| 5.2 Limitations of the Study | 第72-73页 |
| 5.3 Enlightenment for Further Studies | 第73-74页 |
| References | 第74-82页 |
| Acknowledgements | 第82-83页 |
