学校教育是获取知识的主要渠道，但长期以来教育者们关心的不是知识本身，而是传授知识的方式方法。这便是Maton(2014)所说的“知识缺失”。针对这一现象，系统功能语言学和社会教育学做了很多努力和尝试。但正如Martin(2016)所说，还需要寻找更多的知识建构策略。本文试图从语篇内部的权力三项和语篇之间的互文性等两个层面来探讨如何帮助学生认识什么是知识，并掌握学科语篇知识建构的具体策略。

School education is the most important channel for knowledge acquisition. However, what the educators have long been interested in is teaching methodology rather than knowledge itself. To solve the problem of what Karl Maton calls “knowledge blindness”, scholars of both SFL and social pedagogy have made some successful experiments, yet, as Jim Martin points out that further efforts are still needed to find more effective ways to help students to know what knowledge is and how knowledge can be accumulated. This paper attempts to achieve this goal by looking at how power words, power grammar, power composition and intertextuality work in the process of knowledge building in academic discourse.