| Abstract | 第1-14页 |
| 中文摘要 | 第14-16页 |
| List of Tables | 第16-18页 |
| List of Figures | 第18-20页 |
| List of Abbreviations | 第20-22页 |
| Chapter One Introduction | 第22-37页 |
| ·Background of the Study | 第22-25页 |
| ·Rationale for the Study | 第25-28页 |
| ·Purpose and Method of the Study | 第28-31页 |
| ·Significance of the Study | 第31-33页 |
| ·Organization of the Dissertation | 第33-37页 |
| Chapte Two Literature Review | 第37-72页 |
| ·Introduction | 第37-38页 |
| ·Definitions of Lexical Richness | 第38-41页 |
| ·Measures for Lexical Richness | 第41-48页 |
| ·Lexical Density | 第41-42页 |
| ·Lexical Variation | 第42-45页 |
| ·Lexical Sophistication | 第45-47页 |
| ·Word Frequency Distribution | 第47-48页 |
| ·Role of Vocabulary in L2 Writing | 第48-49页 |
| ·Developmental Features of Vocabulary in L2 Writing | 第49-54页 |
| ·Lexical Richness in Writings by L1 and L2 Learners | 第54-56页 |
| ·Lexical Richness and L2 Writing Quality | 第56-60页 |
| ·Lexical Features of L2 Writing | 第60-68页 |
| ·Features of Personal Pronouns | 第60-62页 |
| ·Features of High-frequency Verbs | 第62-63页 |
| ·Features of Modal Auxiliaries | 第63-67页 |
| ·Features of Multi-function Words,Articles and Demonstratives | 第67-68页 |
| ·Research Gaps and Research Questions | 第68-71页 |
| ·Chapter Summary | 第71-72页 |
| Chapter Three Methodology | 第72-103页 |
| ·Introduction | 第72页 |
| ·Special Considerations for the Research Design | 第72-75页 |
| ·The Natural Class Setting | 第73页 |
| ·Same Topic to Students' Interest | 第73-74页 |
| ·Corpus-based Analysis of Language Use | 第74页 |
| ·Objective Rating of Compositions | 第74-75页 |
| ·Participants | 第75-76页 |
| ·Source of Data | 第76-77页 |
| ·Pilot Study | 第77-78页 |
| ·Procedures for Data Collection | 第78-83页 |
| ·Selecting the Universities and the Classes | 第78-79页 |
| ·Orientation for Coordinators | 第79-80页 |
| ·Implementing Writing Tasks | 第80-82页 |
| ·Rating the Compositions | 第82-83页 |
| ·Building the DIY Corpora | 第83-92页 |
| ·Criteria for the Corpus Design | 第83-84页 |
| ·Screening the Written Products | 第84页 |
| ·Computational Processing of the Compositions | 第84-85页 |
| ·Modification of the Compositions | 第85-86页 |
| ·Creating Stop List for Range32 | 第86-87页 |
| ·Grammatical Tagging | 第87-88页 |
| ·Structure of the Corpora | 第88-92页 |
| ·Data Analysis | 第92-101页 |
| ·Tools Used for Data Analysis | 第92-94页 |
| ·Approaches Adopted for Data Analysis | 第94-95页 |
| ·Analyzing the Quantitative Data | 第95-100页 |
| ·Analyzing the Case Study Data | 第100-101页 |
| ·Chapter Summary | 第101-103页 |
| Chapter Four Results and Findings of the Cross-sectional Study | 第103-121页 |
| ·Introduction | 第103页 |
| ·Features of Lexical Variation | 第103-105页 |
| ·Features of Lexical Density | 第105-107页 |
| ·Features of Lexical Sophistication | 第107-110页 |
| ·Features of Word Length | 第110-113页 |
| ·Features of Word Frequency Distribution | 第113-117页 |
| ·Relationship between Lexical Richness and Overall Writing Performance | 第117-120页 |
| ·Chapter Summary | 第120-121页 |
| Chapter Five Results and Findings of the Longitudinal Study | 第121-137页 |
| ·Introduction | 第121页 |
| ·Features of Lexical Variation | 第121-123页 |
| ·Features of Lexical Density | 第123-125页 |
| ·Features of Lexical Sophistication | 第125-127页 |
| ·Features of Word Length | 第127-130页 |
| ·Features of Word Frequency Distribution | 第130-133页 |
| ·Relationship between Lexical Richness and Overall Writing Performance | 第133-136页 |
| ·Chapter Summary | 第136-137页 |
| Chapter Six Results and Findings across the Two Corpora | 第137-154页 |
| ·Introduction | 第137页 |
| ·Patterns and Discrepancies in Lexical Variation | 第137-140页 |
| ·Patterns and Discrepancies in Lexical Density | 第140-142页 |
| ·Patterns and Discrepancies in Lexical Sophistication | 第142-145页 |
| ·Patterns and Discrepancies in Word Length | 第145-147页 |
| ·Patterns and Discrepancies in Word Frequency Distribution | 第147-151页 |
| ·Patterns and Discrepancies in the Relationships between Lexical Richness and Overall Writing Performance | 第151-153页 |
| ·Chapter Summary | 第153-154页 |
| Chapter Seven Results and Findings of the Case Studies | 第154-176页 |
| ·Introduction | 第154页 |
| ·Results of Keyness Analysis | 第154-158页 |
| ·Developmental Features of "we" | 第158-159页 |
| ·Developmental Features of "you" | 第159-161页 |
| ·Developmental Features Of "I" | 第161-162页 |
| ·Developmental Features of "can" | 第162-165页 |
| ·Developmental Features of "know" | 第165-168页 |
| ·Developmental Features of "so" | 第168-174页 |
| ·Chapter Summary | 第174-176页 |
| Chapter Eight Discussion | 第176-214页 |
| ·Introduction | 第176页 |
| ·Overuse of High-frequency Words | 第176-179页 |
| ·Vocabulary Plateau Phenomenon in Lexical Variation | 第179-181页 |
| ·Models of Developmental Features of Lexical Richness | 第181-187页 |
| ·Model of Developmental Features of Lexical Variation | 第182-184页 |
| ·Model of Developmental Features of Lexical Density | 第184-185页 |
| ·Model of Developmental Features of Lexical Sophistication | 第185-187页 |
| ·Unbalanced Efects of Lexical Richness on the Overall Writing Performance | 第187-190页 |
| ·The Most Overused First and Second Personal Pronouns | 第190-201页 |
| ·Rhetorical Differences | 第190-192页 |
| ·Cultural Differences | 第192-195页 |
| ·Writer/Reader Visibility | 第195-198页 |
| ·First Language Transfer | 第198-199页 |
| ·Abnormal Phenomenon of the Overuse of "you" | 第199-201页 |
| ·The Most Overused Modal Auxiliary | 第201-205页 |
| ·The Most Overused Lexical Word | 第205-209页 |
| ·Overuse of "can know" | 第205页 |
| ·Overuse of "As we all know" | 第205-207页 |
| ·Inadequacy in Vocabulary Teaching | 第207-209页 |
| ·The Most Overused Multi-function Word | 第209-212页 |
| ·First Language Interference | 第210-211页 |
| ·Pedagogical Factors | 第211-212页 |
| ·Chapter Summary | 第212-214页 |
| Chapter Nine Conclusion | 第214-234页 |
| ·Summary of the Study | 第214-217页 |
| ·Pedagogical Implications | 第217-230页 |
| ·Adopting Reward System in Evaluating L2 Writings | 第218-219页 |
| ·Turning Receptive Vocabulary into Productive Vocabulary | 第219-220页 |
| ·Integrating Vocabulary Teaching into Writing Instruction | 第220-222页 |
| ·Overcoming Vocabulary Plateau Problem | 第222-224页 |
| ·Reducing Style-interference | 第224-226页 |
| ·Developing Vocabulary Learning Strategies | 第226-227页 |
| ·Launching Corpus-based Vocabulary Teaching | 第227-229页 |
| ·Applying User-friendly Software to Vocabulary Teaching | 第229-230页 |
| ·Limitations of the Study | 第230-231页 |
| ·Suggestions for Future Studies | 第231-232页 |
| ·Concluding Remarks | 第232-234页 |
| References | 第234-256页 |
| Appendix Ⅰ Prompts of the Writing Task | 第256-257页 |
| Appendix Ⅱ Marking Scheme for TEM-4 and TEM-8 Compositions | 第257-258页 |
| Appendix Ⅲ Stop List | 第258-267页 |
| Appendix Ⅳ UCREL CLAWS7 Tagset | 第267-273页 |
| Acknowledgements | 第273-275页 |
| Publications | 第275-276页 |
| 学位论文评阅及答辩情况表 | 第276页 |
