| Acknowledgements | 第1-5页 |
| Abstract | 第5-10页 |
| 摘要 | 第10-13页 |
| Contents | 第13-15页 |
| Chapter I Introduction | 第15-18页 |
| ·Origin of the study | 第15页 |
| ·Necessity and significance of the study | 第15-16页 |
| ·Objectives of the study | 第16-17页 |
| ·Organization of the thesis | 第17-18页 |
| Chapter II Literature Review | 第18-26页 |
| ·Relevant studies abroad | 第18-22页 |
| ·Relevant studies at home | 第22-26页 |
| Chapter III Hedges in Scientific Articles at Different Levels | 第26-40页 |
| ·Hyland's classification | 第26-27页 |
| ·Three levels of hedges in scientific articles | 第27-40页 |
| ·At lexical level | 第27-34页 |
| ·Modal auxiliaries | 第27-29页 |
| ·Epistemic lexical verbs | 第29-31页 |
| ·Epistemic adjectives, adverbs and nouns | 第31-33页 |
| ·Personal pronouns | 第33-34页 |
| ·At syntactic level | 第34-36页 |
| ·Passive voice | 第34-35页 |
| ·Impersonal subjects and nominalization | 第35-36页 |
| ·Conditional and interrogative sentences | 第36页 |
| ·At discourse level | 第36-40页 |
| ·Reference to limited knowledge | 第36-37页 |
| ·Reference to limitations of model, theory or method | 第37-38页 |
| ·Reference to the research work of previous scholars | 第38-40页 |
| Chapter IV Analysis of Hedges in Scientific Articles from CP and PP | 第40-56页 |
| ·From the perspective of Cooperative Principle | 第40-47页 |
| ·Cooperative Principle | 第40-42页 |
| ·Hedges and CP | 第42-44页 |
| ·Interpretation of hedges in scientific articles in the light of CP | 第44-47页 |
| ·From the perspective of politeness | 第47-56页 |
| ·Politeness Principle and Face Theory | 第47-49页 |
| ·Hedges and PP | 第49-51页 |
| ·Interpretation of hedges in scientific articles in the light of PP | 第51-56页 |
| ·Positive politeness strategies | 第51-54页 |
| ·Negative politeness strategies | 第54-56页 |
| Chapter V Functions of Hedges in Scientific Articles | 第56-62页 |
| ·Positive roles | 第56-59页 |
| ·Preciseness, thoughtfulness and flexibility achieved | 第56-57页 |
| ·Writer's responsibility lightened | 第57-58页 |
| ·Writer's modesty and respect showed for the reader | 第58-59页 |
| ·Negative roles | 第59-62页 |
| Chapter VI Conclusion | 第62-65页 |
| ·Major findings of the study | 第62-63页 |
| ·Implications of the study | 第63页 |
| ·Limitations and suggestions for further studies | 第63-65页 |
| Bibliography | 第65-70页 |
| Appendix | 第70页 |
