| Acknowledgements | 第1-5页 |
| Abstract | 第5-8页 |
| 中文摘要 | 第8-10页 |
| Table of Content | 第10-12页 |
| List of Tables and Figures | 第12-13页 |
| List of Abbreviations | 第13-14页 |
| Chapter One Introduction | 第14-17页 |
| ·Need for the Study | 第14-16页 |
| ·Significance of the Study | 第16页 |
| ·Structure of the Thesis | 第16-17页 |
| Chapter Two Literature Review | 第17-33页 |
| ·Key Terms | 第17-20页 |
| ·Definitions of Modality | 第17-18页 |
| ·Modal Auxiliaries | 第18-19页 |
| ·Possibility Modal Verbs | 第19-20页 |
| ·Theoretical Rationale | 第20-23页 |
| ·Modality and Its Categorization | 第20-22页 |
| ·Contrastive Interlanguage Analysis | 第22-23页 |
| ·Related Studies on Modal Verbs | 第23-33页 |
| ·Theoretical Approaches to Modal Verbs | 第23-27页 |
| ·Empirical Studies on Modal Verbs | 第27-33页 |
| Chapter Three Methodology | 第33-49页 |
| ·Research Questions | 第33页 |
| ·Research Design | 第33-49页 |
| ·Data Selection | 第33-35页 |
| ·The Grouping of Corpus Data | 第35-36页 |
| ·Data Analysis | 第36-49页 |
| Chapter Four Results and Discussion | 第49-71页 |
| ·Comparison between Chinese EFL Learners and Native English Speakers | 第49-63页 |
| ·The Overall Picture of can, could, may and might | 第49-50页 |
| ·Semantic Distribution of the Possibility Modals in SECCLS and ICES-GBS | 第50-54页 |
| ·Dynamic Sense of can and could | 第54-57页 |
| ·Problem Types of the Possibility Modals | 第57-63页 |
| ·Comparison between High-achievers and Low-achievers | 第63-71页 |
| ·The Overall Picture of can, could, may and might | 第63-64页 |
| ·Semantic Distribution of the Possibility Modals | 第64-66页 |
| ·Dynamic Sense of can and could | 第66-68页 |
| ·Problem Types of the Possibility Modals | 第68-71页 |
| Chapter Five Conclusion | 第71-75页 |
| ·Major Findings | 第71-73页 |
| ·Pedagogical Implications | 第73-74页 |
| ·Limitations and Suggestions for Future Research | 第74-75页 |
| References | 第75-77页 |
