解决道德教育实效性低的各种策略都忽视了主体道德理性的发挥，不能从根本上解决问题。主体的道德理性实际上存在三个层次：自然层次、原则层次和实践层次。主体的道德理性是在道德判断的过程中形成的，我们至少可以区分出四种不同的道德判断范式。道德教育需要正视道德理性和道德判断的上述特征，在道德判断的过程中促进主体的道德理性发展。

自然概念本身的丰富内涵为从哲学自然到道德自然的转化提供了可能与途径。从“天命”、“天道”、“天理”到“天演”的转换进程，改变了道德的自然展现方式，但却一直在论证着道德的自然正确性。在道德的自然判断过程中，道德理性一直面临着信仰对自身的挑战。道德教育只有处理好信仰与理性之间的难舍关系，道德理性才能自然而然地在主体身上形成。

ACKNOWLEDGEMENTS

CHINESE ABSTRACT

ABSTRACT

CHAPTER ⅠINTRODUCTION

 Background

 Statement of the Problem

 Theoretical Framework

 Research Questions

 Definitions of Key Terms

 Limitations of the Study

CHAPTER Ⅱ REVIEW OF THE LITERATURE

 Aiming at a Conceptual Understanding of Fractions, Decimals and Percents

 External Representations and Internal Representations

 The Role of Different Forms of External Representations in Developing

 Conceptual Understanding of Fractions. Decimals and Percents

 Relationship between Different Forms of Representation and

 Achievements

 The Role of the Textbooks in Facilitating Learning Fractions, Decimals

 and Percents

 Impact of Instructional Time and Teaching Quality on Student

 Achievements

 Theoretical Foundations and Rationale

CHAPTER Ⅲ METHODOLOGY

 Participants

 Instruments

 Number Test

 Quantity Measurement of Instructional Representations

 Quality Measurement of Instructional Representations

 Measurement of Students' Written Representations

 Procedures

 Data Coding

 Data Analysis

CHAPTER Ⅳ RESULTS

 Research Question 1

 Addressing the Mathematics Learning Goals

 Classroom Interactions

 Quantity of Instructional Representations

 Case Example of Quality of Teacher Representation

 Quality of Instructional Representations

 Summary of Results for Research Question 1

 Research Question 2

 Revised Model 1

 Revised Model 2

 Revised Model 3

 Revised Model 4

 Measurement Model of Students' Written Representations

 Model 1

 Model 2

 Research Question 3

 Model 1

 Revised Model 2

 Research Question 4

 Model fit

 Relationship between Instructional Time and Student

 Achievements

 Question 14

 Question 15

 Question 16e

CHAPTER Ⅴ DISCUSSION AND CONCLUSIONS

 Quantity and Quality of Instructional Representations

 Structures of Instructional Representations and Students' Written

 Representations

 Relationship between the Forms of Representations Students Use

 and Their Achievements

 Relationshin between Instructional Reoresentations and Student

 Achievement

 Implications for Future Research

REFERENCES