Chapter 1 Introduction
1.1 Introduction
1.2 Motivation
1.3 Significance of the present study
1.4 Research questions
1.5 Outline of the book

Chapter 2 Curpus linguistics and interlanguage studies
2.1 Corpus linguistics
2.2 Interlanguage
2.3 Learner corpora

Chapter 3 Tense and aspect acquisition and I inguisticfactor⚇，s
3.1 Tense and aspect
3.2 The Present Perfect in English
3.3 Linguistic factors affecting tenseaspect acquisition

Chapter 4 Methodology
4.1 Introduction
4.2 Data description
4.3 Data coding

Chapter 5 Results
5.1 Introduction
5.2 Analysis of tenseaspect errors
5.3 Analysis of the present perfect variation
5.4 Effects of linguistic factors on present perfect variation

Chapter 6 Discussion
6.1 Semantic interpretation of the present perfect variation
6.2 The effects of linguistic factors on the present perfect variation

Chapter 7 Conclusion
7.1 Summary of major findings
7.2 Implications
7.3 Suggestions for future research
Appendix 1 A sample text from CLEC
Appendix 2 Sampled data from tagged VP6 errors on English tenseaspect
Appendix 3 Sampled data from the subjects use of present perfect
Appendix 4 Sampled diagnostic tests for lexical aspect
Bibliography