| Acknowledgements | 第1-4页 |
| Abstract (Chinese) | 第4-5页 |
| Abstract（English） | 第5-9页 |
| 1. Introduction | 第9-17页 |
| ·The Establishment and Development of the Theory of Vagueness | 第9-11页 |
| ·The Place of Pragmatic Functions of Vagueness in the English Language Teaching | 第11-15页 |
| ·The Organization of the Study | 第15-17页 |
| 2. Literature Review | 第17-35页 |
| ·The Definition of Vagueness | 第17-19页 |
| ·The Concepts to Be Clarified | 第19-20页 |
| ·Vagueness | 第19页 |
| ·Generality | 第19-20页 |
| ·Ambiguity | 第20页 |
| ·Sources of Vagueness | 第20-22页 |
| ·Objective Source | 第20-21页 |
| ·Subjective Sources | 第21页 |
| ·Sources from Speakers’Communicative Tactics and Hearers’Ability to Understand | 第21-22页 |
| ·Vagueness in Thinking | 第22-24页 |
| ·Distinctions between Ontological Vagueness and Epistemological Vagueness | 第24-25页 |
| ·The Relationship between Vagueness and Precision in Language | 第25-27页 |
| ·Vagueness in Language | 第25页 |
| ·Precision in Language | 第25-26页 |
| ·The Mutual Conversion of Vagueness and Precision | 第26-27页 |
| ·English Hedges | 第27-30页 |
| ·Classification of Hedges | 第27-28页 |
| ·Pragmatic Functions of Hedges | 第28-30页 |
| ·The Relationship between Pragmatic Function and English Teaching | 第30-33页 |
| ·Summary | 第33-35页 |
| 3. Pragmatic Functions of Vagueness in Language | 第35-44页 |
| ·Giving A Necessary Amount of Information | 第35-36页 |
| ·Withholding Information Deliberately to Evade Speakers’Privacy | 第36-37页 |
| ·For Speakers’Self-Protection or to Their Advantages | 第37页 |
| ·For Better Embodiment of Politeness | 第37-38页 |
| ·Achieving More Persuasive Linguistic Effect | 第38-39页 |
| ·Lacking Words or Expressions | 第39-40页 |
| ·Showing Speakers’Resource and Humor | 第40-41页 |
| ·Lacking Exact Information and Generalizing | 第41页 |
| ·Making conversation informal | 第41-42页 |
| ·Summary | 第42-44页 |
| 4.A Study of Vagueness in the English Language Teaching | 第44-68页 |
| ·Vague phenomena in the English Language Teaching | 第44-51页 |
| ·Vagueness in Pronunciation | 第44-45页 |
| ·Vagueness in Vocabulary | 第45-48页 |
| ·Vagueness in Grammar | 第48-51页 |
| ·Summary | 第51页 |
| ·An Implication of the Uses of Vague Language to English Language Teaching | 第51-68页 |
| ·A Theoretical Analysis | 第51-58页 |
| ·A Questionnaire Research | 第58-64页 |
| ·Discussion | 第64-68页 |
| 5. Conclusion | 第68-70页 |
| ·Main Findings of the Research | 第68-69页 |
| ·Direction for Further Researches | 第69-70页 |
| References | 第70-73页 |
| Appendices | 第73-79页 |
