| ABSTRACT | 第1-7页 |
| 中文摘要 | 第7-11页 |
| LIST OF TABLES | 第11-12页 |
| CHAPTER ONE | 第12-16页 |
| ·OVERVIEW | 第12页 |
| ·NEED FOR THE PRESENT STUDY | 第12-14页 |
| ·STRUCTURE OF THE THESIS | 第14-16页 |
| CHAPTER TWO | 第16-32页 |
| ·BASIC CONCEPTS | 第16-24页 |
| ·Studies on definition of a word | 第16-18页 |
| ·Receptive vs. productive vocabulary | 第18-20页 |
| ·Some measures of lexical richness | 第20-24页 |
| ·RELATED THEORIES | 第24-28页 |
| ·Separate trait models | 第24-25页 |
| ·Global trait models | 第25-28页 |
| ·RELATED EMPIRICAL STUDIES | 第28-31页 |
| ·SUMMARY | 第31-32页 |
| CHAPTER THREE | 第32-43页 |
| ·RESEARCH QUESTIONS | 第32页 |
| ·RESEARCH DESIGN | 第32-35页 |
| ·Material | 第32-33页 |
| ·Corpus description | 第33页 |
| ·A description of TEM-Band 4 and TEM-Band 8 oral test | 第33-35页 |
| ·Task 2 in TEM-Band 4 and task 3 in TEM-Band 8 oral test | 第35页 |
| ·DATA PROCESSING | 第35-39页 |
| ·Data collecting | 第35-37页 |
| ·Data clarifying | 第37-39页 |
| ·Data analyzing | 第39页 |
| ·TOOLS FOR DATA PROCESSING | 第39-42页 |
| ·SUMMARY | 第42-43页 |
| CHAPTER FOUR | 第43-51页 |
| ·DIFFERENCES IN LEXICAL VARIATION | 第43-46页 |
| ·Differences in lexical variation of learners between Year Two and Year Four | 第43-44页 |
| ·Differences in lexical variation of high-level learners of Year Two and Year Four | 第44-45页 |
| ·Differences in lexical variation of low-level learners of Year Two and Year Four | 第45-46页 |
| ·DIFFERENCES IN LEXICAL SOPHISTICATION | 第46-49页 |
| ·Differences in lexical sophistication of learners between Year Two and Year Four | 第46-47页 |
| ·Differences in lexical sophistication of high-level learners between Year Two and Year Four | 第47-48页 |
| ·Differences in lexical sophistication of low-level learners between Year Two and Year Four | 第48-49页 |
| ·SUMMARY | 第49-51页 |
| CHAPTER FIVE | 第51-54页 |
| ·MAJOR FINDINGS | 第51-52页 |
| ·PEDAGOGICAL IMPLICATIONS | 第52-53页 |
| ·LIMITATIONS | 第53页 |
| ·RECOMMENDATIONS FOR FUTURE RESEARCH | 第53-54页 |
| REFERENCES | 第54-58页 |
| APPENDIX I | 第58-64页 |
| APPENDIX II | 第64-69页 |
