| 摘要 | 第1-6页 |
| ABSTRACT | 第6-10页 |
| Chapter One Introduction | 第10-14页 |
| ·Origin of the Idea | 第10-11页 |
| ·Background of the Study | 第11-12页 |
| ·Significance of the Study | 第12-13页 |
| ·Organization of the Thesis | 第13-14页 |
| Chapter Two Literature Review | 第14-32页 |
| ·Definitions of Lexical Chunks | 第14-17页 |
| ·Classifications of Lexical Chunks | 第17-22页 |
| ·Classifications based on Form | 第17-20页 |
| ·Classifications based on Function | 第20-22页 |
| ·Roles of Lexical Chunks in Language Acquisition | 第22-26页 |
| ·Facilitating Language Processing | 第22-23页 |
| ·Promoting Fluency and Accuracy of Language Production | 第23-24页 |
| ·Helping Enhance Communicative Language Ability | 第24-25页 |
| ·Arousing Language Learners' Motivation | 第25-26页 |
| ·Lexical Chunks under the Perspective of Cognition | 第26-28页 |
| ·Lexical Chunks and Chunking Theory | 第26-27页 |
| ·Lexical Chunks and Connectionism | 第27-28页 |
| ·Lexical Chunks in Written Discourse | 第28-29页 |
| ·The Transactional View and the Interactional View of Functions of Language | 第28-29页 |
| ·Lexical Chunks in Transactional Written Discourse | 第29页 |
| ·Retrospective Studies about Lexical Chunks in China | 第29-32页 |
| Chapter Three Research Design | 第32-36页 |
| ·Objectives and Research Questions | 第32页 |
| ·Subject | 第32-33页 |
| ·Instruments | 第33-34页 |
| ·Research Procedure | 第34-36页 |
| Chapter Four Analysis and Discussion | 第36-59页 |
| ·The Relationship between Students' Writing Performance and Lexical Chunks Usage | 第36-39页 |
| ·The General Description of Four Categories of Lexical Chunks | 第39-40页 |
| ·Within-group Comparison on Four Categories of Lexical Chunks | 第40-42页 |
| ·Between-group Comparison on Four Categories of Lexical Chunks | 第42-46页 |
| ·Characteristics of Lexical Chunks in Students' Writing | 第46-51页 |
| ·Lexical Chunks Learning Attitudes in High-score Group and Low-score group | 第51-54页 |
| ·Usage of Lexical Chunks in Writing Practice in High-score Group and Low-score Group | 第54-59页 |
| Chapter Five Conclusions,Pedagogical Implications and Limitations | 第59-64页 |
| ·Findings | 第59-60页 |
| ·Pedagogical Implications | 第60-63页 |
| ·Limitations and Suggestions for Further Research | 第63-64页 |
| Bibliography | 第64-68页 |
| Appendix Ⅰ The Writing Test | 第68-69页 |
| Appendix Ⅱ IELTS Task 2 Writing Band Descriptors | 第69-72页 |
| Appendix Ⅲ Questionnaire | 第72-74页 |
| Appendix Ⅳ Scores of Writings and the Number of Lexical Chunks Used inthe Writings | 第74-77页 |
| Appendix Ⅴ Total Number of Chunks and the Four Categories Distribution ofChunks | 第77-80页 |
| Acknowledgements | 第80-81页 |
| Publications | 第81页 |
