| 摘要 | 第5-6页 |
| Abstract | 第6-7页 |
| Chapter One Introduction | 第12-16页 |
| 1.1 Research Background | 第12-14页 |
| 1.2 Research Purpose | 第14页 |
| 1.3 Significance of the Present Study | 第14-15页 |
| 1.4 Structure of the Present Study | 第15-16页 |
| Chapter Two Literature Review | 第16-28页 |
| 2.1 Definition of Lexical Richness | 第17-18页 |
| 2.2 Lexical Richness in L 1 and L2 Writings | 第18-23页 |
| 2.2.1 Comparative Studies on Lexical Richness in Writings by L 1 and L2 Learners | 第18-21页 |
| 2.2.2 Studies on Lexical Richness in Writings by Chinese Learners | 第21-23页 |
| 2.3 The Relationship between Lexical Richness and Writing Quality | 第23-28页 |
| 2.3.1 Studies on Relationship between Lexical Richness and Writing Quality Abroad | 第23-25页 |
| 2.3.2 Studies on Relationship between Lgxical Richness and Writing Quality at Home | 第25-28页 |
| Chapter Th ree Methods | 第28-37页 |
| 3.1 Research Questions | 第28页 |
| 3.2 Participants | 第28页 |
| 3.3 Data Collection | 第28-30页 |
| 3.4 Analytical Framework | 第30-35页 |
| 3.4.1 Lexical Variation | 第30-32页 |
| 3.4.2 Lexical Sophistication | 第32-34页 |
| 3.4.3 Lexical Density | 第34-35页 |
| 3.5 Instruments | 第35-36页 |
| 3.6 Summary | 第36-37页 |
| Chapter Four Results and Discussion | 第37-54页 |
| 4.1 Results of Writing Scores | 第37-38页 |
| 4.2 Results of Lexical Variation,Lexical Sophistication and Lexical density | 第38-42页 |
| 4.3 Results of Correlations among Lexical Variation,Lexical Sophistication and Lexical Density | 第42-44页 |
| 4.4 Results of Independent Samples Tests of Lexical Richness | 第44-47页 |
| 4.5 Results of Correlations between Lexical Richness and Writing Quality | 第47-49页 |
| 4.6 Discussion | 第49-52页 |
| 4.6.1 Distribution of Lexical Variation, Lexical Sophistication and Lexical Density | 第49-50页 |
| 4.6.2 Correlations among Lexical Variation, Lexical Sophistication and Lexical Density | 第50-51页 |
| 4.6.3 Results of Independent Samples Tests of Lexical Richness | 第51页 |
| 4.6.4 Correlations between Lexical Richness and Writing Quality | 第51-52页 |
| 4.7 Summary | 第52-54页 |
| Chapter Five Conclusion | 第54-60页 |
| 5.1 Major Findings | 第54-56页 |
| 5.2 Pedagogical Implications | 第56-57页 |
| 5.2.1 Implications for Vocabulary Learning and Teaching | 第56-57页 |
| 5.2.2 Implications for Second Language Writing | 第57页 |
| 5.3 Limitations | 第57-58页 |
| 5.4 Suggestions for Future Study | 第58-60页 |
| Bibliography | 第60-64页 |
| Appendix 1 Writing Task | 第64-65页 |
| Appendix 2 Sample Essays | 第65-68页 |
| Appendix 3 Rating Criteria | 第68-69页 |
| Acknowledgements | 第69-70页 |
| 个人简历 | 第70页 |
| 发表的学术论文 | 第70页 |
