**3. Metacognitive knowledge**

Metacognition includes two components (see **Figure 1**), the knowledge of metacognition and metacognitive regulation (e.g., [1–4]). Metacognitive knowledge refers to the awareness of what one does and does not know [28]. McCormick [29] divided metacognitive knowledge into three separate components. The first is *declarative* knowledge, or what the readers know about the texts they read [3, 30]/ second, *procedural* knowledge, involves the ability to apply their knowledge by using a particular strategy effectively and efficiently to complete a given task [31]. For instance, readers may find it useful to look at pictures or headings before they begin to read a passage, while others may prefer to re-read the previous sentence to understand the current sentence that they are reading. Finally, the third element of metacognitive knowledge is *conditional* knowledge, which refers to readers' knowledge about the what, where, when, whom, how, and why that is necessary to use a particular metacognitive strategy; it also refers to the readers'

**Figure 1.**

*Metacognitive types based upon [1–4, 27].*

ability to understand the situation, which strategy would be best, why they should use this strategy, and how to apply the particular strategy to make sense of the text [3, 32].

Other scholars have divided metacognitive knowledge differently, indicating that knowledge contains three elements: self-characteristics, task characteristics, and taskrelevant strategies [3, 27, 29, 31]. Self-characteristics include the ability to read and the skills required to reach the goal of learning. Task characteristics are related to reading levels and the material's difficulty, and they also involve the reader's familiarity with the reading tasks. Finally, task-relevant strategies refer to the metacognitive strategies that readers must use to comprehend the text [29].
