| Acknowledgements | 第5-6页 |
| Abstract | 第6-7页 |
| 摘要 | 第8-12页 |
| Chapter One Introduction | 第12-16页 |
| 1.1 Research Background | 第12-13页 |
| 1.2 Research Purpose | 第13-14页 |
| 1.3 Significance of the Research | 第14页 |
| 1.4 Structure of the Thesis | 第14-16页 |
| Chapter Two Literature Review | 第16-36页 |
| 2.1 Definition and Classifications of Language Attrition | 第16-19页 |
| 2.1.1 Definition of Language Attrition | 第16-18页 |
| 2.1.2 Classifications of Language Attrition | 第18-19页 |
| 2.2 Factors Influencing Foreign Language Lexical Attrition | 第19-27页 |
| 2.2.1 Length of the Attrition Period | 第20-22页 |
| 2.2.2 Initial Proficiency Level | 第22-23页 |
| 2.2.3 Exposure to the Target Language in the Attrition Period | 第23-24页 |
| 2.2.4 Lexical Factors | 第24-27页 |
| 2.3 Other Related Studies on Lexical Attrition Abroad | 第27-32页 |
| 2.3.1 At Macro-level | 第27-28页 |
| 2.3.2 At Micro-level | 第28-32页 |
| 2.4 Previous Studies on Lexical Attrition at Home | 第32-33页 |
| 2.4.1 Theoretical Studies | 第32-33页 |
| 2.4.2 Empirical Studies | 第33页 |
| 2.5 Strengths and Weaknesses of the Previous Studies | 第33-36页 |
| Chapter Three Theoretical Framework | 第36-40页 |
| 3.1 The Inverse Hypothesis | 第36-37页 |
| 3.2 The Activation Threshold Hypothesis | 第37-38页 |
| 3.3 The Retrieval Failure Hypothesis | 第38-40页 |
| Chapter Four Methodology | 第40-48页 |
| 4.1 Research Questions | 第40页 |
| 4.2 Subjects | 第40-41页 |
| 4.3 Instruments | 第41-45页 |
| 4.3.1 English Vocabulary Test | 第41-44页 |
| 4.3.2 Questionnaire | 第44-45页 |
| 4.4 Procedures | 第45-46页 |
| 4.5 Data Collection and Analysis | 第46-48页 |
| Chapter Five Results and Discussion | 第48-64页 |
| 5.1 Presentation of Results | 第48-59页 |
| 5.1.1 Lexical Attrition of Students with Different Proficiencies | 第48-52页 |
| 5.1.2 Correlation between the Amount of Exposure and Lexical Attrition | 第52-53页 |
| 5.1.3 Attrition of Words of Different Word Classes | 第53-54页 |
| 5.1.4 Word Classes of Attrition of Students with Different Proficiencies | 第54-56页 |
| 5.1.5 Attrition of Words of Different Word Lengths | 第56-57页 |
| 5.1.6 Word Lengths of Attrition of Students with Different Proficiencies | 第57-59页 |
| 5.2 Discussion | 第59-64页 |
| 5.2.1 Influence of the Initial English Proficiency on Lexical Attrition | 第59-61页 |
| 5.2.2 Influence of the Amount of Exposure to English during Summer Vacation onLexical Attrition | 第61页 |
| 5.2.3 Relationship between Lexical Attrition and Vocabulary Linguistic Features | 第61-64页 |
| Chapter Six Conclusion | 第64-68页 |
| 6.1 Major Findings | 第64-65页 |
| 6.2 Pedagogical Implications | 第65-66页 |
| 6.3 Limitations of the Research | 第66-67页 |
| 6.4 Suggestions for Future Research | 第67-68页 |
| References | 第68-76页 |
| Appendices | 第76-89页 |
