Text Structure, Purpose, and Main Idea
What this domain tests
This domain asks whether a third grader can see how a text is built and why it was written. Candidates should understand the main idea and how details support it, the author's purpose (to inform, persuade, or entertain), and common text structures such as sequence, compare and contrast, cause and effect, and problem and solution. They should recognize titles and headings as signals of topic, and how a paragraph stays on one idea.
Traps in questions
A frequent trap is a choice that is a supporting detail rather than the main idea, or a main idea that is too broad or too narrow. Another trap is confusing purpose: a story about a real event may entertain rather than inform. Signal words such as "because," "first," "however," and "both" can point to structure, and questions may test whether a student notices them.
Rule of thumb
Ask "What is this mostly about?" and choose the idea that covers the whole passage, not just one sentence. Then check the purpose with "Is the author teaching, convincing, or telling a story?"
Worked example
Passage: "Recycling saves space in landfills. It also saves energy. Finally, it turns old materials into new products." Asked for the main idea: choices are "Landfills are full," "Recycling has many benefits," "New products are expensive," "Energy is important." The details all support benefits of recycling. Answer: "Recycling has many benefits."