Introduction
1 Research Background
2 Statement of the Problem
3 Purpose of the Study
4 Conceptual Framework
5 Organization of the Dissertation

Chapter One Literature Review
Introduction
1.1 Online Language Learning
1.1.1 Online Education
1.1.2 Research Status of Online Language Learning
1.1.3 Foreign Language Learning
1.2 Benefits of Online Education
1.2.1 Organizational Framework of Online Learning Community
1.2.2 Sense of Community
1.3 Learners' Continuance Intention Toward Online Education"
1.3.1 TAM
1.3.2 ECM
1.4 Interaction in Distance Education
1.4.1 Definition
1.4.2 Instructional Interaction
1.4.3 System Interactivity
1.5 Equivalence Theory
1.5.1 Online Interactions with Learners
1.5.2 Equivalence Theory
1.6 Interaction Hypothesis ��IH��
1.6.1 VersionsoflH
1.6.2 Deficiencies of IH
1.7 Socio-cultural Theory
1.7.1 ZPD
1.7.2 Mediation
1.7.3 Language�� as a Symbolic Tool for Mediation
1.8 Scaffolding
1.8.1 Metaphor and Definition
1.8.2 Features and Functions of Scaffolding
1.8.3 Design of Scaffolding in Online Education
Summary

Chapter Two Research Model and Hypotheses
Introduction
2.1 Interaction in Online Language Learning
2.1.1 Interactivity and Scaffolding
2.1.2 Scaffolding Sources Versus Preconditions
2.1.3 Scaffolding Features and Dimensions
2.1.4 Scaffolding Dimensions and Scaffolding Types
2.2 Online Interaction and Continuance Intention
2.2.1 TAM
2.2.2 ECM
2.2.3 Sense of Community
2.2.4 Interaction Construction
2.2.5 Second-Order Construct of Scaffolding
Summary

Chapter Three Methodology
Introduction
3.1 Survey Instrument
3.1.1 0perationalizing the Second-Order Construct of Scaffolding
3.1.2 Developing the Survey Instrument
3.2 Pilot Test
3.3 Participants and Procedure
3.4 Analysis and Results
3.4.1 The Measurement Model
3.4.2 Common Method Bias
3.4.3 Hypothesis Testing
Summary

Chapter Four Discussion
Introduction
4.1 Online Interaction Construction
4.1.1 Integral Constituents of Online Interaction
4.1.2 Construction of Scaffolding
4.2 Correlation Between Interaction and Continuance Intention
Summary

Chapter Five Contributions and Implications
Introduction
5.1 Theoretical Contributions
5.2 Practical Implications
Summary

Conclusion
1 Summary of Contributions
2 Limitations
3 Directions for Future Research
Bibliography
Appendix
Appendix A: List of Items by Construct
Appendix B: Measurement Instrument
Appendix C: Chinese Version of Measurement Instrument.-
Appendix D: Construct Reliabilities�� AVE and Correlations-
Appendix E: Item Loadings and Cross-Loadings