| 摘要 | 第1-7页 |
| Abstract | 第7-12页 |
| Chapter One Introduction | 第12-14页 |
| ·Purpose and significance of the study | 第12-13页 |
| ·Overall structure of the thesis | 第13-14页 |
| Chapter Two Literature Review | 第14-36页 |
| ·Past linguistic researches on modal auxiliaries | 第14-23页 |
| ·Classification of modal auxiliaries | 第14-18页 |
| ·Monosemantic model | 第15页 |
| ·Category model | 第15-16页 |
| ·Fuzzy set model | 第16-18页 |
| ·Semantic meaning of the selected modal auxiliaries | 第18-21页 |
| ·MUST and HAVE TO | 第18-20页 |
| ·SHOULD and OUGHT TO | 第20-21页 |
| ·NEED TO | 第21页 |
| ·Pragmatic meaning to express politeness | 第21-23页 |
| ·Past non-linguistic researches on modal auxiliaries | 第23-36页 |
| ·Language and cultural transfer | 第24-31页 |
| ·Language and culture | 第24-25页 |
| ·Definition of culture | 第25-26页 |
| ·Cultural transfer | 第26-31页 |
| ·Eastern and western cultures | 第31-36页 |
| ·Features of western culture | 第31-33页 |
| ·Features of eastern culture | 第33-36页 |
| Chapter Three The Empirical Study | 第36-47页 |
| ·Research objectives | 第36-38页 |
| ·Method | 第38-45页 |
| ·Subjects | 第38-39页 |
| ·Instruments | 第39-41页 |
| ·Data collection | 第41-44页 |
| ·Administration | 第41-42页 |
| ·Typing | 第42页 |
| ·Softwares used | 第42-44页 |
| ·Subjective scoring | 第44-45页 |
| ·Questionare | 第45页 |
| ·Summary | 第45-47页 |
| Chapter Four Results and Discussion | 第47-65页 |
| ·Results of objective measure | 第47-60页 |
| ·Word frequency in group | 第47-49页 |
| ·Comparison on selected modal auxiliary | 第49-60页 |
| ·Comparison on MUST between two grades | 第49-52页 |
| ·Comparison on HAVE TO between two grades | 第52-54页 |
| ·Comparison on SHOULD between two grades | 第54-56页 |
| ·Comparison on OUGHT TO between two grades | 第56-58页 |
| ·Comparison on NEED TO between two grades | 第58-60页 |
| ·Results of subjective measure | 第60-61页 |
| ·Discussion on modal auxiliary and mood | 第61-65页 |
| Chapter Five Conclusions | 第65-73页 |
| ·Major findings | 第65-67页 |
| ·Differences of frequency in using modal auxiliaries | 第65-66页 |
| ·Reflected pragmatic ability in using modal auxiliaries | 第66-67页 |
| ·Comprehensive causation analysis | 第67-69页 |
| ·Complex pragmatic quality | 第67-68页 |
| ·Cultural transfer | 第68-69页 |
| ·Implications | 第69-70页 |
| ·Limitations and future study | 第70-73页 |
| ·Limitations | 第71页 |
| ·Suggestions for future study | 第71-73页 |
| References: | 第73-77页 |
| Appendix Ⅰ | 第77-78页 |
| Appendix Ⅱ | 第78-80页 |
| Appendix Ⅲ | 第80-81页 |
| Acknowledgement | 第81页 |
