| Acknowledgements | 第1-7页 |
| Abstract | 第7-9页 |
| 内容摘要 | 第9-11页 |
| Chapter One Introduction | 第11-16页 |
| ·Rationale for the study | 第11-13页 |
| ·Purpose of the present study | 第13-14页 |
| ·Research questions | 第14页 |
| ·Organization of the dissertation | 第14-16页 |
| Chapter Two Literature Reviews | 第16-35页 |
| ·Epistemic modality and its related concepts | 第16-22页 |
| ·Modality | 第16-18页 |
| ·Epistemic modality | 第18-19页 |
| ·Epistemic devices | 第19-22页 |
| ·Grammatical knowledge of epistemic modality | 第22-24页 |
| ·Syntactic features | 第22-23页 |
| ·Semantic features | 第23-24页 |
| ·Pragmatic ability in using epistemic modality | 第24-29页 |
| ·Functions of epistemic modality | 第24-29页 |
| ·Expressing attitudes toward a proposition | 第25页 |
| ·Mitigating or intensifying an illocutionary force | 第25-26页 |
| ·Exhibiting personal involvement | 第26-27页 |
| ·Avoiding unnecessary risks | 第27-28页 |
| ·Dissociating from the proposition | 第28-29页 |
| ·Development of the acquisition of epistemic modality | 第29-35页 |
| ·Interlanguage development of epistemic modality | 第29-30页 |
| ·Pragmatic development of epistemic modality | 第30-35页 |
| ·Frequency of modifiers used | 第31-32页 |
| ·Range of modifiers used | 第32-35页 |
| Chapter Three Research Methodology | 第35-44页 |
| ·Participants | 第35页 |
| ·Materials | 第35-42页 |
| ·One measurement of the general grammatical knowledge | 第36-37页 |
| ·One measurement of the specific grammatical knowledge of using epistemic markers | 第37-40页 |
| ·One measurement of the specific pragmatic ability in using epistemic markers | 第40-42页 |
| ·Data analysis procedures | 第42-44页 |
| Chapter Four Results and Discussion | 第44-56页 |
| ·Results analysis | 第44-50页 |
| ·Answering two research questions | 第44-50页 |
| ·Discussion | 第50-56页 |
| ·Discussion 1 | 第51-52页 |
| ·Discussion 2 | 第52-54页 |
| ·Personality | 第52-53页 |
| ·Attitudes and motivation | 第53-54页 |
| ·Discussion 3 | 第54-56页 |
| Chapter Five Conclusion | 第56-61页 |
| ·Pedagogical implications and suggestions | 第56-60页 |
| ·Limitations of the present research | 第60-61页 |
| References | 第61-66页 |
| Appendix Ⅰ General Grammatical Test | 第66-74页 |
| Appendix Ⅱ Specific Grammar Test | 第74-77页 |
| Appendix Ⅲ Specific Pragmatic Test | 第77-78页 |
