| Abstract | 第1-6页 |
| Chapter 1 Introduction | 第6-8页 |
| 1．1 Background of the study | 第6-7页 |
| 1．2 Overview of the paper | 第7-8页 |
| Chapter 2 Literature Review | 第8-34页 |
| 2．1 The investigation of the relationship between SLA and LT | 第8页 |
| 2．2 Investigation of the interfaces between SLA and LT | 第8-10页 |
| 2．2．1 Investigations of the interfaces between SLA and LT | 第8-9页 |
| 2．2．2 The interfaces between SLA and LT | 第9-10页 |
| 2．3 Developments of guiding linguistic theories in language testing | 第10-16页 |
| 2．3．1 Performance assessment | 第12-15页 |
| 2．3．2 The characteristics of performance assessment | 第15-16页 |
| 2．4 Task-based writing assessment | 第16-23页 |
| 2．4．1 Defining "task" | 第16-17页 |
| 2．4．2 The characteristics of writing | 第17-18页 |
| 2．4．3 Comparison between testing of writing and other objective testing | 第18页 |
| 2．4．4 Models of writing process | 第18-20页 |
| 2．4．5 Problems with the present writing teaching and testing in China | 第20-21页 |
| 2．4．6 The research done on writing in recent years | 第21-22页 |
| 2．4．7 Why task-based language assessment? | 第22-23页 |
| 2．5 How to assess the task difficulty/complexity factors? | 第23-28页 |
| 2．5．1 Task Difficulty and task complexity | 第23-24页 |
| 2．5．2 The meaning and characteristics of task difficulty | 第24-26页 |
| 2．5．3 The meaning and characteristics of task complexity | 第26-27页 |
| 2．5．4 The interactive demands of task complexity, task difficulty and task conditions | 第27-28页 |
| 2．6 Recent studies in task difficulty and task complexity | 第28-34页 |
| 2．6．1 The task-based research done in oral production | 第28-32页 |
| 3．6．2 The task-based research done in written production | 第32-33页 |
| 3．6．3 The implications for the task-based writing assessment | 第33-34页 |
| Chapter 3 The Present Study | 第34-56页 |
| 3．1 The Experiment | 第34-36页 |
| 3．1．1 The subjects | 第34-35页 |
| 3．1．2 The selection of writing topics | 第35页 |
| 3．1．3 Research questions | 第35页 |
| 3．1．4 The procedure and research methods | 第35-36页 |
| 3．2 Analysis of the students' writings with different difficulty levels | 第36-47页 |
| 3．2．1 Analysis of the influence of difficulty on the students' writing performance | 第36-39页 |
| 3．2．2 The relationship between the students' scores and the performance variables | 第39-41页 |
| 3．2．3 The relationship between the students' scores and their perception of the task difficulty | 第41-45页 |
| 3．2．4 The influence of task conditions | 第45-47页 |
| 3．3 Analysis of the students' writing with different complexity levels | 第47-56页 |
| 3．3．1 Analysis of the influence of complexity on the students' writing performance | 第47-49页 |
| 3．3．2 The relationship between the students' scores and their performance variables | 第49-51页 |
| 3．3．3 The relationship between the students' performances and their perception of task complexity | 第51-54页 |
| 3．3．4 The influence of task conditions | 第54-56页 |
| Chapter Ⅳ Conclusion | 第56-61页 |
| 4．1 The findings of the research | 第56-57页 |
| 4．2 Implications for syllabus design | 第57-58页 |
| 4．3 Pedagogical implications | 第58-59页 |
| 4．4 The adaptation of the affect in the task performance | 第59-60页 |
| 4．5 Limitations of the present study and suggestions for future study | 第60-61页 |
| References． | 第61-65页 |
| Appendix (Ⅰ) | 第65-71页 |
| Appendix (Ⅱ) | 第71-94页 |
| Appendix (Ⅲ) | 第94-96页 |
| Acknowledgement | 第96页 |
