| Acknowledgements | 第1-5页 |
| Abstract | 第5-7页 |
| 摘要 | 第7-9页 |
| Contents | 第9-12页 |
| List of Tables and Figures | 第12-13页 |
| Chapter One Introduction | 第13-17页 |
| ·Origin of the study | 第13-14页 |
| ·Necessity and significance of the study | 第14-15页 |
| ·Objectives of the study | 第15页 |
| ·Organization of the thesis | 第15-17页 |
| Chapter Two Literature Review | 第17-35页 |
| ·Studies on reporting | 第17-26页 |
| ·Definition of reporting | 第17-18页 |
| ·Various approaches to reporting | 第18-22页 |
| ·The philosophical approach | 第18页 |
| ·The stylistic approach | 第18-19页 |
| ·The structural approach | 第19-21页 |
| ·The pragmatic and functional approach | 第21-22页 |
| ·Other relevant studies on reporting | 第22-25页 |
| ·Reporting studies in academic theses | 第22-23页 |
| ·Reporting studies in news reports | 第23-25页 |
| ·Summary | 第25-26页 |
| ·Studies on vagueness | 第26-35页 |
| ·Previous studies on the definition of vagueness | 第26-30页 |
| ·Definitons of vagueness | 第26-28页 |
| ·Clarification of some terms: fuzziness, vagueness, generality and ambiguity | 第28-30页 |
| ·Studies on hedges | 第30-32页 |
| ·Definitons of hedges | 第30-31页 |
| ·Major classifications of hedges | 第31-32页 |
| ·Definition and linguistic realizations of vagueness in reporting source in the present study | 第32-34页 |
| ·Summary | 第34-35页 |
| Chapter Three Methodology | 第35-49页 |
| ·Research questions | 第35页 |
| ·Two corpora | 第35-38页 |
| ·Criteria of data collection | 第36页 |
| ·Corpora employed | 第36-38页 |
| ·Learners' corpus: WECCL2.0 | 第37页 |
| ·Reference corpus: NESSIE 1.0 | 第37-38页 |
| ·Instruments | 第38-42页 |
| ·AntConc 3.2.4w | 第38-40页 |
| ·BFSU CQPweb | 第40页 |
| ·Log-likelihood Ratio Calculator | 第40-42页 |
| ·The Contrastive Interlanguage Analysis approach | 第42页 |
| ·Data collection and analysis procedures | 第42-49页 |
| ·Approaches to identifying vagueness in reporting source | 第42-45页 |
| ·Identification of reporting and reporting verbs | 第42-44页 |
| ·Identification of linguistic realizations of vagueness in reporting source | 第44-45页 |
| ·Research procedures | 第45-49页 |
| Chapter Four Results and Discussion | 第49-67页 |
| ·The overview of vague reporting source use in Chinese English learners argumentative writings | 第49-60页 |
| ·The overall frequency of vague reporting source in Chinese English learners' argumentative writings | 第49-53页 |
| ·Using features of vague reporting source in each realization | 第53-59页 |
| ·Frequencies and distributions of lexical devices and syntactic devices of vague reporting source | 第53-54页 |
| ·Frequencies and distributions of vague reporting source in each realization | 第54-59页 |
| ·Summary | 第59-60页 |
| ·Features of vague reporting source use by Chinese English learners with different proficiency levels | 第60-65页 |
| ·The overview of vague reporting source between high-level Chinese learners and low-level Chinese learners | 第60-62页 |
| ·Similarites and differences in the distributions of various realizations of vagueness in reporting between the two groups of Chinese learners | 第62-65页 |
| ·Frequencies and distributions of two devices of vague reporting source | 第62-63页 |
| ·Frequencies and distributions of vague reporting source in each realization | 第63-65页 |
| ·Summary | 第65-67页 |
| Chapter Five Conclusion | 第67-71页 |
| ·Major findings of the study | 第67-68页 |
| ·Implications of the study | 第68-69页 |
| ·Limitations of the study and suggestions for further research | 第69-71页 |
| Works Cited | 第71-75页 |
| Appendices | 第75-77页 |
| Appendix A | 第75-76页 |
| Appendix B | 第76-77页 |
| Publications | 第77页 |
