| Acknowledgements | 第1-6页 |
| 摘要 | 第6-7页 |
| Abstract | 第7-10页 |
| Chapter 1 Introduction | 第10-14页 |
| ·Background of the Research | 第10-11页 |
| ·Purpose and Significance of the Thesis | 第11-12页 |
| ·Layout of the Thesis | 第12-14页 |
| Chapter 2 Literature Review | 第14-27页 |
| ·Related Concepts of Deontic Modality | 第15-19页 |
| ·Main Expressions of Deontic Modality | 第15-16页 |
| ·Values of Deontic Modality | 第16-17页 |
| ·Orientation System of Deontic Modality | 第17-19页 |
| ·Distinction between Deontic Modality and Modal Responsibility | 第19-21页 |
| ·Definition of Deontic Modality Expressivity | 第21页 |
| ·Previous Studies about Deontic Modality | 第21-27页 |
| Chapter 3 Research Methodology | 第27-33页 |
| ·Research Questions | 第27-28页 |
| ·Data Collection | 第28-31页 |
| ·Research Procedures | 第31-33页 |
| Chapter 4 Results and Discussion | 第33-63页 |
| ·Deontic Modality Expressivity in Political Speeches | 第34-42页 |
| ·Deontic Modality Expressions Analysis | 第34-37页 |
| ·Deontic Modality Value Analysis | 第37-40页 |
| ·Deontic Modality Orientation and Meaning Analysis | 第40-42页 |
| ·Deontic Modality Expressivity in Business English | 第42-55页 |
| ·Deontic Modality Expressions Analysis | 第42-47页 |
| ·Deontic Modality Value Analysis | 第47-53页 |
| ·Deontic Modality Orientation and Meaning Analysis | 第53-55页 |
| ·Contrastive Analysis of Deontic Modality Expressivity in Political Speeches and Business English | 第55-59页 |
| ·Expressivity Similarities | 第56-58页 |
| ·Expressivity Differences | 第58-59页 |
| ·Causes for Similarities and Differences | 第59-63页 |
| ·Discourse Style Factors | 第59-60页 |
| ·Pragmatic Factors | 第60-63页 |
| Chapter 5 Conclusion | 第63-67页 |
| Works Cited | 第67-70页 |
| 攻读硕士学位期间发表的论文和取得的科研成果 | 第70-71页 |
| Appendix Ⅰ Political Speeches | 第71-78页 |
| Appendix Ⅱ Business English Discourse | 第78-86页 |
