有別於先前研究主要比較學科內容與語言綜合學習課程(CLIL)與非學科內容與語言綜合學習課程(non-CLIL)的差異，本研究旨在探討第二外語寫作在學科內容與語言綜合學習課程(CLIL)中，句法複雜度、正確度以及流暢度的發展情形。在為期十八週的課程當中，本研究分別蒐集了十九位英語作為外國語學生的學期初，學期中以及學期末的課後寫作，共五十七篇的作業進行分析，在比較學生學期三階段句法複雜度、正確度以及流利度之後，研究結果顯示學生正確度與流暢度有顯著進步，但複雜度並無顯著差異，此結果說明學科內容與語言綜合學習課程對於第二外語寫作有部分的助益，本研究並提出學生正確度與流暢度進步的原因可能是因為評分者對於寫作的糾正回饋、作業評量標準以及練習效應，根據研究結果，文章最後提出相關教學啟示以及方法。

Unlike previous studies that placed their primary focus on the comparison between CLIL and non-CLIL classes, this study aimed to explore L2 writing development in a CLIL class by examining authentic texts from the class. 19 participants participated an 18-week CLIL class and a total of 57 written assignments from the beginning, the middle, and the final phase of the course were collected. By analyzing syntactic complexity, syntactic accuracy, and fluency across three different times, the findings revealed that the participants improved their accuracy and fluency but not complexity, suggesting that a CLIL class was beneficial for L2 writing improvement to some extent. Possible accounts for accuracy and fluency improvement include corrective feedback on grammar, criteria of written assignments, and practice effects. Further pedagogical implications were provided in response to the findings.