| Abstract | 第1-6页 |
| 摘要 | 第6-10页 |
| Introduction | 第10-14页 |
| Chapter One Literature Review | 第14-22页 |
| ·Vagueness and vague language | 第14-16页 |
| ·Vague language research | 第16-20页 |
| ·Vague language research abroad | 第17-19页 |
| ·Vague language research at home | 第19-20页 |
| ·Summary | 第20-22页 |
| Chapter Two Darwin's Theory of Evolution | 第22-27页 |
| ·Adaptation and selection in biology | 第22-23页 |
| ·Necessity of adaptation and selection in biology | 第23-24页 |
| ·Verschueren's theory of linguistic adaptation and Darwin's evolutionary theory | 第24-26页 |
| ·Summary | 第26-27页 |
| Chapter Three Adaptation and Language Selection | 第27-35页 |
| ·Adaptation and selection in language | 第27-30页 |
| ·Necessity of adaptation and selection in language | 第30-32页 |
| ·Adaptation as the principle of language selection | 第32-33页 |
| ·Summary | 第33-35页 |
| Chapter Four Vague Language | 第35-47页 |
| ·The necessity of vague language in communication | 第35-36页 |
| ·Sources of vague language | 第36-40页 |
| ·Classifications of vague language | 第40-42页 |
| ·Pragmatic functions of vague language | 第42-46页 |
| ·Contributing appropriateness of language | 第43-44页 |
| ·Making utterances reserved | 第44页 |
| ·Making utterances polite | 第44-45页 |
| ·Filling lexical gaps | 第45页 |
| ·Producing aesthetic effects | 第45-46页 |
| ·Summary | 第46-47页 |
| Chapter Five Adaptation and Vague Language Selection | 第47-66页 |
| ·Adaptation to the mental world and vague language selection | 第47-55页 |
| ·Adaptation to speaker's motivations | 第47-53页 |
| ·Giving the right amount of information | 第48-50页 |
| ·Withholding information deliberately | 第50-51页 |
| ·Meeting the need for self-protection | 第51-52页 |
| ·Meeting the need for esteem | 第52-53页 |
| ·Adaptation to emotions | 第53-55页 |
| ·Adaptation to the social world and vague language selection | 第55-61页 |
| ·Adaptation to social cultures | 第56-57页 |
| ·Adaptation to the communicator's social position | 第57-58页 |
| ·Adaptation to the communicator's profession | 第58-60页 |
| ·Adaptation to the communicator's gender | 第60-61页 |
| ·Adaptation to the physical world and vague language selection | 第61-64页 |
| ·Adaptation to the objective physical world | 第61-63页 |
| ·Adaptation to the subjective physical world | 第63-64页 |
| ·Summary | 第64-66页 |
| Conclusion | 第66-70页 |
| Bibliography | 第70-74页 |
| Appendix | 第74-76页 |
| Acknowledgements | 第76-78页 |
