Language is a multi-level system consisting of phonology, semantics and syntax. Therefore, when we study language we should cope with the whole text to increasingly further its frontier. Discourse analysis studies texture at various configurative levels, and one of its important parts is text structure. The coherence and cohesion of texture is the symbol of a successful text, and one of the focuses of EFL writing. This thesis attempts to analyze the thematic structure within the framework of Halliday's Systemic-Functional Grammar, and how it functions in text coherence and the practical meaning of the application of this theory to the teaching of EFL writing.Writing, as the practice of the comprehensive English skill, is one of the difficult devices to be manipulated for English learners, for it is the embodiment of the communicative abilities. Writers often meet with difficult problems in the process of writing such as where to start with, how to connect adjacent sentences or paragraphs and so on and so forth. The deep root lies in that although the learners may master the syntax of the target language, the want of the cognition and sensibility towards the text structure and the organization rules of it may also lead to the failure of communication. As such is the case, that what it is that has to be learnt in order to produce effective written products have become the main concern of English teachers.The eventual aim of this paper is to provide information for EFL writing teachers, which will assist them in preparing students for successful writing. After study, we find that Theme is an aspect of language, which looks likely to yield useful information in this connection. By comparing Chinese EFL students' writings with that of the natives', it seems that many Chinese EFL students have different choices of thematic structure and thematic progression patterns compared with that of the native speakers. Theme does, then, appear to be a possible problem area in EFL writing and, as such, it would seem worth keeping on further investigation. |