| ACKNOWLEDGEMENTS | 第5-6页 |
| ABSTRACT | 第6-7页 |
| 摘要 | 第8-9页 |
| CONTENTS | 第9-11页 |
| LIST OF TABLES | 第11页 |
| LIST OF FIGURES | 第11-12页 |
| CHAPTER ONE INTRODUCTION | 第12-16页 |
| 1.1 BACKGROUND OF THE RESEARCH | 第12-13页 |
| 1.2 SIGNIFICANCE OF THE RESEARCH | 第13-14页 |
| 1.3 LAYOUT OF THE THESIS | 第14-16页 |
| CHAPTER TWO LITERATURE REVIEW | 第16-25页 |
| 2.1 HEDGES IN THE LITERATURE | 第16-21页 |
| 2.1.1 DEFINING HEDGES | 第16-18页 |
| 2.1.2 CLASSIFICATIONS OF HEDGES | 第18-21页 |
| 2.2 PREVIOUS RESEARCHES ON HEDGES | 第21-24页 |
| 2.2.1 RESEARCHES OF HEDGES ABROAD | 第21-23页 |
| 2.2.2 RESEARCHES OF HEDGES AT HOME | 第23-24页 |
| 2.3 FORMAT AND PURPOSE OF AMERICAN PRESIDENTIAL DEBATE | 第24-25页 |
| CHAPTER THREE THEORETICALFRAMEWORK | 第25-30页 |
| 3.1 THE THEORY OF METAFUNCTION | 第25-27页 |
| 3.1.1 IDEATIONAL FUNCTION | 第25-26页 |
| 3.1.2 INTERPERSONAL FUNCTIONS | 第26-27页 |
| 3.2 COOPERATIVE PRINCIPLE | 第27-28页 |
| 3.3 POLITENESS PRINCIPLE | 第28-30页 |
| CHAPTER FOUR RESEARCH METHODOLOGY | 第30-33页 |
| 4.1 RESEARCH QUESTIONS | 第30页 |
| 4.2 DATA COLLECTION | 第30-32页 |
| 4.3 RESEARCH METHODS AND PROCEDURE | 第32-33页 |
| CHAPTER FIVE QUANTITATIVEANALYSIS OF HEDGES IN THE DEBATES | 第33-41页 |
| 5.1 FREQUENCY AND DISTRIBUTION OF DIFFERENT TYPES OF HEDGES | 第33-36页 |
| 5.2 DIFFERENCES IN HEDGE USES BETWEEN OBAMA AND ROMNEY | 第36-41页 |
| 5.2.1 THE DIFFERENCES OF HEDGES | 第36-38页 |
| 5.2.2 REASONS FOR THE DIFFERENCES | 第38-41页 |
| CHAPTER SIXA NALYSIS OF HEDGES FROM THE PERSPECTIVE OF THEMETAFUNCTION THEORY | 第41-70页 |
| 6.1 IDEATIONAL FUNCTIONS OF HEDGES IN POLITICAL DEBATES | 第41-45页 |
| 6.1.1 TO INCREASE FUZZINESS | 第42-43页 |
| 6.1.2 TO DECREASE FUZZINESS | 第43-45页 |
| 6.2 INTERPERSONAL FUNCTIONS OF HEDGES IN POLITICAL DEBATES | 第45-56页 |
| 6.2.1 HEDGES AS A COOPERATIVE STRATEGY | 第46-53页 |
| 6.2.2 HEDGES AS A POLITENESS STRATEGY | 第53-56页 |
| 6.3 PRAGMATIC FUNCTIONS OF HEDGES IN POLITICAL DEBATES | 第56-70页 |
| 6.3.1 TO ENHANCE CREDIBILITY | 第56-58页 |
| 6.3.2 TO ATTACK OPPONENTS | 第58-60页 |
| 6.3.3 TO GIVE RELATIVELY ACCURATE INFORMATION | 第60-62页 |
| 6.3.4 TO PROTECT ONESELF | 第62-65页 |
| 6.3.5 TO SHOW POLITENESS | 第65-67页 |
| 6.3.6 TO BUILD A FUTURE VISION | 第67-70页 |
| CHAPTER SEVEN CONCLUSION | 第70-74页 |
| 7.1 MAJOR FINDINGS | 第70-72页 |
| 7.2 IMPLICATIONS OF THE RESEARCH | 第72页 |
| 7.3 LIMITATIONS AND SUGGESTIONS FOR FURTHER RESEARCH | 第72-74页 |
| REFERENCES | 第74-77页 |
| APPENDIX | 第77-84页 |
| APPENDIX A | 第77-79页 |
| APPENDIX B | 第79-82页 |
| APPENDIX C | 第82-84页 |
