| ACKNOWLEDGEMENTS | 第6-7页 |
| 摘要 | 第7-9页 |
| Abstract | 第9-10页 |
| List of Abbreviations | 第14-17页 |
| CHAPTER ONE INTRODUCTION | 第17-21页 |
| 1.1 Need for the Study | 第18-20页 |
| 1.2 Overview of the Thesis | 第20-21页 |
| CHAPTER TWO LITERATURE REVIEW | 第21-40页 |
| 2.1 Definitions of Key Terms | 第21-24页 |
| 2.1.1 Definition of frequency | 第21-22页 |
| 2.1.2 Definition of FSs | 第22-23页 |
| 2.1.3 Integrated writing task | 第23-24页 |
| 2.2 Classification of FSs | 第24-28页 |
| 2.2.1 Structural perspective | 第24-27页 |
| 2.2.2 Functional perspective | 第27-28页 |
| 2.3 Theoretical Foundation | 第28-32页 |
| 2.3.1 Task frequency in usage-based theory | 第28-29页 |
| 2.3.2 Dual nature of language | 第29-31页 |
| 2.3.3 Dual-mode of language processing | 第31-32页 |
| 2.4 Review of Related Studies | 第32-38页 |
| 2.4.1 Studies on frequency | 第32-35页 |
| 2.4.2 Studies on the use of formulaic sequences | 第35-38页 |
| 2.5 Research Gaps | 第38-40页 |
| CHAPTER THREE METHODOLOGY | 第40-49页 |
| 3.1 Research Questions | 第40-41页 |
| 3.2 Participants | 第41页 |
| 3.3 Instruments | 第41-42页 |
| 3.4 Data Collection | 第42页 |
| 3.5 Data Analysis | 第42-49页 |
| 3.5.1 Identifying FSs | 第42-44页 |
| 3.5.2 Classifying FSs | 第44-45页 |
| 3.5.3 Classifying erroneous FSs | 第45-47页 |
| 3.5.4 Tallying FSs | 第47-48页 |
| 3.5.5 Statistical analysis | 第48-49页 |
| CHAPTER FOUR RESULTS AND DISCUSSION | 第49-78页 |
| 4.1 Frequency Effects on the Use of FSs in L2 Integrated Writing | 第49-64页 |
| 4.1.1 Changes in the number of FSs | 第49-56页 |
| 4.1.1.1 Changes in the number of different categories of FSs | 第51-54页 |
| 4.1.1.2 Changes in the numbers of prompt and non-prompt FSs | 第54-56页 |
| 4.1.2 Changes in accuracy of FSs | 第56-61页 |
| 4.1.2.1 Changes in accuracy of different categories of FSs | 第57-59页 |
| 4.1.2.2 Changes in accuracy of prompt and non-prompt FSs | 第59-61页 |
| 4.1.3 Error types of FSs | 第61-63页 |
| 4.1.4 Summary of frequency effects on the use of FSs in writing | 第63-64页 |
| 4.2 Frequency Effects on the Use of FSs in L2 Integrated Writing by Learners at Different Proficiency Levels | 第64-78页 |
| 4.2.1 Changes in the number of FSs used by learners at different proficiency levels | 第64-69页 |
| 4.2.1.1 Changes in the number of different categories of FSs used by learners at different proficiency levels | 第65-68页 |
| 4.2.1.2 Changes in the number of prompt and non-prompt FSs for learners at different proficiency levels | 第68-69页 |
| 4.2.2 Changes in the accuracy of FSs used by learners at different proficiency levels | 第69-72页 |
| 4.2.2.1 Changes in the accuracy of different categories of FSs used by learners at different proficiency levels | 第70-71页 |
| 4.2.2.2 Changes in the accuracy of prompt and non-prompt FSs used by learners at different proficiency levels | 第71-72页 |
| 4.2.3 Error types of FSs used by learners at different proficiency levels | 第72-76页 |
| 4.2.4 Summary of frequency effects on the use of FSs in writing of learners at different proficiency levels | 第76-78页 |
| CHAPTER FIVE CONCLUSION | 第78-84页 |
| 5.1 Major Findings | 第78-80页 |
| 5.1.1 Frequency effects on the use of FSs in L2 integrated writing | 第78-79页 |
| 5.1.2 Frequency effects on the use of FSs in L2 integrated writing by learners at different proficiency levels | 第79-80页 |
| 5.2 Implications | 第80-81页 |
| 5.3 Limitations of the Present Study and Suggestions for Future Research | 第81-84页 |
| REFERENCES | 第84-90页 |
| APPENDIXES | 第90-94页 |
| Appendix A: Source Texts and Writing Prompt | 第90-92页 |
| Appendix B: An Annotated Sample of one Student's Writing | 第92-94页 |
