英文作文教學在英語學習上是不可或缺的一環，而實際上在台灣，英文作文教學仍是透過分析文法和句型來進行的，但這樣的方式忽略了英文寫作能夠成功的主要關鍵——連貫性。由於連貫性的晦澀難解，教師與學生皆會認為在教授和學習寫出有連貫性的文章是很複雜的。本文藉由教導學生如何於寫作時運用連繫功能詞(cohesive devices)和主題推進(thematic progression)兩種策略來探究作文中的連貫性，以研究其增進高中生英文寫作表現的可能性。本研究在不影響正常教學進度的前提下進行，研究者的39位臺北市高二學生首先接受如何分析課本文章連貫性的指導，並接著應用和檢視連繫功能詞以及主題推進於他們的寫作中。其中有兩位低成就者進一步地被挑選出來，藉由寫作會談(writing conference)以瞭解受試者在寫作時，如何利用以上兩種連貫性的策略於其英文寫作中；同時也透過訪談和日記撰寫的方式，來探討學生的學習連貫性策略的歷程。 由相關的量化和質性資料可看出，本研究的結果顯示受試者在作文整體表現與作文連貫性上的分數明顯偏高；他們也被證明能夠和其他研究中的高成就者一般，運用相同的連繫功能詞(指稱、連接與重述)和主題推進(線性推進與主題連續推進)種類。在這歷時五個月的研究中，受試者也在連繫功能詞與主題推進的協助下，培養出更注意作文內容以及進行適當修改的能力。此外，也由於受試者對於學習連繫功能詞與主題推進抱持著正面的態度，本研究建議應結合連繫功能詞和主題推進，並將其融入台灣現存的正規作文教學之中，藉著分析作文中的連繫功能詞與主題推進，協助學生理解抽象的連貫性進而使作文表現更進步。 / As an indispensable element in English learning, writing instruction in Taiwan actually has been given through the analysis of grammar and sentence patterns. This however ignores another primary key to successful writing—coherence. Due to its obscurity, teachers and students both find it complicated to teach and acquire the ability to organize a written text logically and coherently. The current study investigated the possibility to improve the high school students’ writing by instructing them how to apply the coherence strategies to their writing—cohesive devices (CD) and thematic progression (TP). In this study, with the teaching schedule unaffected, the researcher’s 39 second-graders in one Taipei senior high school were first taught how to analyze the coherence of the reading passages in the textbooks. Then they were required to apply and examine CD and TP when writing. Two low achievers of these students were further selected to investigate their writing development by examining their written texts with CD and TP applied in writing conferences, having interviews with the researcher and keeping journals between classes and writing conferences. Concluded from the quantitative and qualitative data collected, the results revealed that the two low-proficiency students were able to get high grades in the holistic writing performance and coherence of writing. They were meanwhile found to be able to apply the same categories of CD (reference, conjunction and reiteration) and types of TP (simple linear TP type and TP with a constant theme) as the ones used by the high-proficiency learners in previous studies. During the five-month study, the participants also cultivated the ability to focus more on content level and to revise properly in their writing with the help of CD and TP. Besides, since the participants held positive attitudes toward the learning of CD and TP, the researcher recommends that the combination of CD and TP should be integrated into the writing instruction in current normal English writing class in Taiwan to help students comprehend the abstract coherence and to improve their writing by analyzing CD and TP in the written texts.