3 MT presentations have emerged as an important academic genre, helping graduate students to present disciplinary knowledge to wide audiences. While previous research has investigated the structuring of presentations, little is known about the rhetorical features students employ to persuade their diverse listenership. In this study, we draw on Hyland’s (2005) stance and engagement framework to explore how the popularisation of scientific knowledge has influenced the ways presenters interact with their audiences. Based on a 3 MT corpus of 80 presentations from six disciplines, the results show that stance markers are more often used than listener engagement markers, while explicit mentions of self and listeners are the most common features. Additionally, presenters in the hard sciences, compared to those in soft-knowledge fields, make more use of the interactional features, but rhetorical questions are more frequently used in the soft knowledge fields. Therefore, we see this nuanced use of stance and engagement as related to the rhetorical contexts of register, genre and disciplinary propositional content. Pedagogical implications raised include developing students’ ability in the popularisation of science and their raising their awareness of disciplinary knowledge and its social relevance.

3 MT演讲已经成为一种重要的学术体裁，可以帮助研究生向广泛的受众介绍学科知识。尽管先前的研究已经研究了演讲的结构，但对于学生用来说服他们的不同听众的修辞特征知之甚少。在本研究中，我们借鉴海兰德（Hyland，2005）的立场和参与框架来探讨科学知识的普及如何影响演讲者与听众互动的方式。根据来自6个学科的80场演讲的3 MT语料库，结果表明，姿势标记比听者参与标记更常用，而自我和听者的明确提及是最常见的特征。此外，与软知识领域的演讲者相比，硬科学领域的演讲者 充分利用了交互功能，但修辞问题在软知识领域中更为常用。因此，我们看到这种与立场，语气和学科命题内容的修辞语境有关的立场和参与的细微差别。所产生的教学意义包括发展学生在科学普及中的能力，以及提高他们对学科知识及其社会意义的认识。