| Acknowledgements | 第1-8页 |
| Abstract in English | 第8-10页 |
| Abstract in Chinese | 第10-11页 |
| Preface | 第11-14页 |
| Chapter One An Introduction to Critical Period Hypothesis | 第14-21页 |
| ·Basic Information about Critical Period | 第14-18页 |
| ·Definitions of CP | 第14-16页 |
| ·CP in Human Cognitive Domains and Other Species | 第16-18页 |
| ·Critical Period Hypothesis: a debatable topic | 第18-20页 |
| ·Lennerberg and Critical Period Hypothesis (CPH) | 第18-20页 |
| ·Questions to be Solved | 第20页 |
| ·Summary | 第20-21页 |
| Chapter Two A Critical Review of the Critical Period Hypothesis in Second Language Learning | 第21-32页 |
| ·Introduction | 第21页 |
| ·A Review of the Four Positions in Second Language Learning | 第21-31页 |
| ·Position One:the Younger, the Better | 第21-27页 |
| ·Position Two:the older, the better | 第27-28页 |
| ·Position Three:the younger=better at acquiring accent | 第28-29页 |
| ·Position four:the younger, the better in the long run | 第29-31页 |
| ·Summary | 第31-32页 |
| Chapter three Age In Second Language Learning | 第32-40页 |
| ·Neurolinguistic Studies | 第32-34页 |
| ·Lenneberg's Five Reasons of Certain Biological Peculiarities for Human Linguistic Ability | 第32-33页 |
| ·Functions of Human Brain | 第33页 |
| ·Human Nervous System | 第33-34页 |
| ·Summary | 第34页 |
| ·Child-Adult Differences and Advantages in Second Language Learning | 第34-35页 |
| ·Age and Correctness of Pronunciation in Second Language Learning | 第35-36页 |
| ·A Brief Review | 第35-36页 |
| ·The Author's View | 第36页 |
| ·Social Environmental Factor | 第36-38页 |
| ·Motivations in second language learning | 第38-40页 |
| Chapter Four Conclusions | 第40-45页 |
| ·The Four Theoretical Positions in the Research of CPH | 第40页 |
| ·Neurolinguistic Study | 第40-41页 |
| ·Child Second Language Learners and Adult Second Language Learners | 第41-42页 |
| ·Age and the Correctness in Pronunciation of Second Language | 第42页 |
| ·Social Environment and CPH | 第42-43页 |
| ·The Factor of Motivation in Second Language Learning | 第43页 |
| ·Summary | 第43-45页 |
| Appendix | 第45-46页 |
| References | 第46-49页 |
