元话语实现交互功能，是命题意义之外的意义成分，包括作者组织语篇、与读者互动以及表达对命题内容与对读者态度的显性手段。本文选择了一类学术语域特征突出、却尚未得到关注的小句级元话语资源———功能句干，重点考察其作为框架语、内指语和证据来源语的特征性引导元话语功能。从话语策略角度，我们将框架句干归类为“定点”元话语资源，将内指句干和证据来源句干归为“连线”元话语资源。研究发现，学术作者通过综合运用“定点”、“连线”等元话语策略来有效管理命题信息、合理组织语篇结构、引导读者按其希望的方式理解文本内容，从而实现“学术互动”的交际目的。

Metadiscourse embodies interactions. It is the meaning component of a discourse beyond its propositional aspects, including the explicit means of organizing a discourse, interacting with the reader, as well as expressing the writer’s attitude toward either its content or the reader. This paper investigates a type of clause-level metadiscourse resources that are characteristic of academic English but have not aroused wide interest, namely, Functional Sentence Stems (FSSs), with a view to characterizing their most prominent interactive metadiscourse functions as frame markers, endophoric markers, and evidentials. In terms of discourse strategies, we classify frame markers under “locating” resources, while endophoric markers and evidentials under “linking” resources. It is found that the academic writer tactically use both discourse strategies to effectively manage information, organize discourse, direct the reader’s reception of the text in a way preferred by the writer, and hereby to realize the communicative goal of “academic interaction”.