| Acknowledgments | 第1-5页 |
| 摘要 | 第5-7页 |
| Abstract | 第7-9页 |
| Contents | 第9-12页 |
| List of Tables | 第12-13页 |
| Chapter One Introduction | 第13-17页 |
| ·Research Background | 第13-14页 |
| ·Research Questions | 第14-15页 |
| ·Organization of the Thesis | 第15-17页 |
| Chapter Two Literature Review | 第17-31页 |
| ·Overseas Studies on Null Subjects in Second Language Acquisition | 第17-21页 |
| ·Overseas Studies on Null Objects in Second Language Acquisition | 第21-22页 |
| ·Overseas Studies on the Asymmetry between Null subjects and Null Objects in Second Language Acquisition | 第22-26页 |
| ·Domestic Studies on Null Subjects and Null objects in Second Language Acquisition | 第26-29页 |
| ·Summary | 第29-31页 |
| Chapter Three Theoretical Framework | 第31-37页 |
| ·The UG Theory | 第31页 |
| ·Role of UG in Second Language Acquisition | 第31-32页 |
| ·Differences on Subjects and Objects between Chinese and English | 第32-36页 |
| ·From the Perspective of Pro-drop Parameter | 第32-33页 |
| ·From the Perspective of Topic Constructions | 第33-35页 |
| ·From the Perspective of Objects | 第35-36页 |
| ·Summary | 第36-37页 |
| Chapter Four Empirical Study | 第37-51页 |
| ·Hypotheses | 第37-38页 |
| ·Subjects | 第38-39页 |
| ·Instruments | 第39-40页 |
| ·Scoring | 第40-41页 |
| ·Results | 第41-50页 |
| ·Difference between Unlearning of Null subjects and Null Objects | 第41-43页 |
| ·Unlearning of Null Subjects and Null Objects in Matrix and Embedded Sentences31 | 第43-46页 |
| ·Unlearning of Null Referential Subjects and Null Expletive Subjects | 第46-48页 |
| ·Difference among the Three Groups | 第48-50页 |
| ·Summary | 第50-51页 |
| Chapter Five Discussion | 第51-63页 |
| ·Unlearning of Null Subjects and Null Objects | 第51-55页 |
| ·Unlearning of Null Subjects and Null Objects in Matrix and Embedded Sentences | 第55-57页 |
| ·Learners’ Better Performance on Unlearning of Null Arguments in Matrix Sentences than in Embedded Sentences | 第55-56页 |
| ·Learners’ Better Performance on Unlearning of Null Subjects in Embedded Sentences than in Matrix Sentences | 第56-57页 |
| ·Unlearning of Null Referential Subjects and Null Expletive Subjects | 第57-60页 |
| ·Unlearning of Null Referential Subjects and Null Expletive Subjects | 第57-59页 |
| ·Acquisition of Expletive Subject ‘it’ and ‘there’ | 第59-60页 |
| ·Explanations for the Difference among the Three Groups | 第60-61页 |
| ·Summary | 第61-63页 |
| Chapter Six Conclusion | 第63-67页 |
| ·Summary of the Major Findings | 第63-64页 |
| ·Limitations of the Study and Suggestions for Future Research | 第64页 |
| ·Pedagogical Suggestions | 第64-67页 |
| Bibliography | 第67-73页 |
| Appendix A | 第73-77页 |
| Appendix B | 第77-81页 |
| Appendix C | 第81-84页 |
