| ACKNOWLEDGEMENTS | 第9-10页 |
| ABSTRACT | 第10页 |
| 摘要 | 第11-14页 |
| CHAPTER I INTRODUCTION | 第14-17页 |
| 1.1 Research Background | 第14-15页 |
| 1.2 Significance of the Study | 第15页 |
| 1.3 Overall Organization of the Thesis | 第15-17页 |
| CHAPTER II LITERATURE REVIEW | 第17-31页 |
| 2.1 Introduction of Vague Language | 第17-19页 |
| 2.2 Introduction of Hedges | 第19-24页 |
| 2.2.1 Definition of Hedges | 第19-20页 |
| 2.2.2 Classifications of Hedges | 第20-24页 |
| 2.3 Previous Studies on Hedges | 第24-28页 |
| 2.3.1 Studies on Hedges Abroad | 第24-26页 |
| 2.3.2 Studies on Hedges at Home | 第26-28页 |
| 2.4 Previous Studies on Commencement Addresses | 第28-31页 |
| 2.4.1 Studies on Commencement Addresses Abroad | 第28-29页 |
| 2.4.2 Studies on Commencement Addresses at home | 第29-31页 |
| CHAPTER III RESEARCH METHODOLOGY | 第31-35页 |
| 3.1 Research Questions | 第31页 |
| 3.2 Data Collection | 第31-32页 |
| 3.3 Procedures of Data Analysis | 第32-34页 |
| 3.4 Research Methods | 第34-35页 |
| CHAPTER IV ANALYSIS OF HEDGES IN UNIVERSITY PRESIDENTS' COMMENCEMENT ADDRESSES | 第35-61页 |
| 4.1 Overall Distribution of Hedges in the Data | 第35-39页 |
| 4.2 Use of Lexical Hedges | 第39-51页 |
| 4.2.1 Modal Auxiliary Verb Hedges | 第39-43页 |
| 4.2.2 Modal Lexical Verb Hedges | 第43-45页 |
| 4.2.3 Adjectival, Adverb and Nominal Hedges | 第45-49页 |
| 4.2.4 Hedges Realized by Approximators | 第49-51页 |
| 4.3 Use of Non-lexical Hedges | 第51-55页 |
| 4.3.1 Syntactic Level Hedges in American University Presidents' Commencement Addresses | 第51-54页 |
| 4.3.2 Discourse Level Hedges in American University Presidents' Commencement Addresses | 第54-55页 |
| 4.4 Functions of Hedges in University Presidents' Commencement Addresses.. | 第55-61页 |
| 4.4.1 To Make the Language More Persuasive | 第55-56页 |
| 4.4.2 To Promote Addressors' Confidence | 第56-57页 |
| 4.4.3 To Show Addressors' Responsibility | 第57-58页 |
| 4.4.4 To Establish a Unique and Indispensable Image | 第58页 |
| 4.4.5 To Express Politely and Appropriately | 第58-59页 |
| 4.4.6 To Shorten the Distance with the Graduates | 第59-61页 |
| CHAPTER Ⅴ CONCLUSION | 第61-64页 |
| 5.1 Major Findings of the Study | 第61-62页 |
| 5.2 Limitations of the Study | 第62页 |
| 5.3 Further Suggestions | 第62-64页 |
| REFERENCES | 第64-67页 |
| APPENDIX | 第67-68页 |
