| Acknowledgements | 第1-6页 |
| Abstract | 第6-9页 |
| Chapter 1 Modality | 第9-19页 |
| ·Modality as a Communicative Strategy | 第9-10页 |
| ·Development of the Concept | 第10-11页 |
| ·Types of Modality and Related Concepts | 第11-19页 |
| ·The Three-way Categorizing | 第12-17页 |
| ·Epistemic Modality | 第12-13页 |
| ·Deontic Modality | 第13-15页 |
| ·Dynamic Modality | 第15-17页 |
| ·Subjective and Objective Modalities | 第17页 |
| ·Theoretical and Factual Modalities | 第17-19页 |
| Chapter 2 Research into Modal Auxiliaries | 第19-30页 |
| ·Modality Research from the Point of View of Grammar | 第19-21页 |
| ·Modality Research from the Point of View of Logic | 第21-22页 |
| ·Modality Research from the Point of View of Semantics | 第22-28页 |
| ·Tense and Time | 第23-25页 |
| ·Negation | 第25-27页 |
| ·Interrogation | 第27-28页 |
| ·Modality Research from the Point of View of Cognition | 第28-30页 |
| Chapter 3 Previous Methods of Analysis | 第30-39页 |
| ·The Polysemy View | 第30-33页 |
| ·The Monosemy View | 第33-34页 |
| ·The Fuzzy-set View | 第34-37页 |
| ·Method of Analysis in this Paper | 第37-39页 |
| Chapter 4 Main Senses of can and may | 第39-50页 |
| ·Senses of the Modal Verb can | 第39-45页 |
| ·Sense 'ability' of the Modal Verb can | 第39-40页 |
| ·Sense 'possibility' of the Modal Verb can | 第40-43页 |
| ·Sense 'permission' of the Modal Verb can | 第43-44页 |
| ·Summary | 第44-45页 |
| ·Senses of the Modal Verb may | 第45-50页 |
| ·Sense 'ability' of the Modal Verb may | 第45页 |
| ·Sense 'possibility' of the Modal Verb may | 第45-46页 |
| ·Sense 'permission' of the Modal Verb may | 第46-48页 |
| ·Summary | 第48-50页 |
| Chapter 5 Comparison Between can and may | 第50-58页 |
| ·Comparison Between can and may | 第50-54页 |
| ·Derived Relationships Among 'ability', 'possibility' and 'permission' | 第54-58页 |
| Chapter 6 Implications for Language Learners and Teachers | 第58-61页 |
| ·Implication for English Language Learners | 第58-60页 |
| ·Implication for English Language Teachers | 第60-61页 |
| Chapter 7 Conclusions and Suggestions for Further Research | 第61-65页 |
| ·Summary of the Research | 第61-62页 |
| ·Limitation of the Present Study and Suggestion for Further Research | 第62-65页 |
| Bibliography | 第65-68页 |
