| Acknowledgements | 第1-6页 |
| Abstract | 第6-8页 |
| 中文摘要 | 第8-13页 |
| Chapter One Introduction | 第13-17页 |
| ·Need for the study | 第13-15页 |
| ·Significance of the study | 第15-16页 |
| ·Structure of the thesis | 第16-17页 |
| Chapter Two Literature Review | 第17-33页 |
| ·Conception of connectives | 第17-22页 |
| ·Definition of contrastive connectives | 第17-18页 |
| ·Classification of contrastive connectives | 第18-21页 |
| ·Halliday and Hasan’s classification | 第18-19页 |
| ·Biber et al.’s classification | 第19页 |
| ·Quirk et al.’s classification | 第19-21页 |
| ·The position of contrastive connectives | 第21-22页 |
| ·Differences of but and however | 第22页 |
| ·Some theories related to this study | 第22-28页 |
| ·Theories on cohesion | 第23-24页 |
| ·Interlanguage | 第24-25页 |
| ·Language transfer | 第25-26页 |
| ·Error analysis | 第26-28页 |
| ·Definition of error | 第26-27页 |
| ·Significance of study on language errors | 第27-28页 |
| ·Previous studies on contrastive connectives | 第28-33页 |
| ·Empirical studies of contrastive connectives at abroad | 第28-30页 |
| ·Studies of contrastive connectives in China | 第30-31页 |
| ·Limitations of the previous studies | 第31-33页 |
| Chapter Three Methodology | 第33-43页 |
| ·Research questions | 第33页 |
| ·The description of the two corpora | 第33-35页 |
| ·The learner corpus | 第34页 |
| ·The native corpus | 第34-35页 |
| ·Research methods | 第35页 |
| ·Data preparation | 第35-36页 |
| ·Data analyzing procedures | 第36-43页 |
| Chapter Four Results and Discussion | 第43-58页 |
| ·General characteristics of use of but and however | 第43-52页 |
| ·Overall frequency of use of but and however | 第43-44页 |
| ·Types of use of but and however in terms of context | 第44-47页 |
| ·Types of use of but | 第44-46页 |
| ·Types of use of however | 第46-47页 |
| ·The over- use, under-use and misuse of but and however in ST4 | 第47-52页 |
| ·The over- and under-use of but | 第47-48页 |
| ·The over- and under-use of however | 第48-50页 |
| ·Misuse of but and however | 第50-52页 |
| ·Differences in use of but and however on learners’writing proficiency | 第52-58页 |
| Chapter Five Conclusion | 第58-62页 |
| ·Major findings | 第58-60页 |
| ·Pedagogical implications | 第60页 |
| ·Limitations and suggestions for future research | 第60-62页 |
| References | 第62-63页 |
