在非以英語為母語的國家中，高等教育使用英語授課愈趨普遍，但英語授課並非全然的品質保證。由於目前關於國內外英語授課的研究，缺乏以課室觀察與了解學生觀點的方式進行，探討大學專業教師如何協助學生學習，更值得學界重視。本文採質性個案研究方式，旨在探討大學專業教師如何以英語設計課程與引導學生，期待未來能協助教師有效教學。本文以臺灣四位教學成效受到同事與學生的肯定的大學專業教師為參與者，透過分析教師與學生訪談及課室教學觀察資料，指出教師如何使用三種多層次的教學方式(參與性、連結性、與擴大性)，以促進學生對專業內容、認知、與文化方面的學習。此外，對於專業教師缺乏語言目標與使用的發現，也點出語言與專業教師合作的重要性。本文最後將針對未來研究及語言與專業教師如何有效合作提出建議。

The prevalence of English-medium instruction (EMI) in non-native English speaking (NNES) universities by no means guarantees effective teaching. Since little is understood about NNES university instructors’ classroom instruction, it is pedagogically significant to examine how they support student learning. Using a qualitative case study, this paper explores four Taiwanese content teachers’ classroom practices to explore effective guidance for students’ learning of content via English. These instructors were perceived as competent by their colleagues and students. Their interview and observation data were collected and triangulated by student interview data. The findings identified the use of engaging, bridging, and amplifying at a multi-layered level to achieve content, cognitive, and cultural objectives. The limited attention to language objectives and use underscore the primacy of the collaboration between content and language teachers in facilitating NNES content teachers’ professional development. In this respect, approaches to effective EMI by language and content teachers as well as directions for future research are specified in the conclusion.