SAT Text Structure and Purpose
Identify why a text was written, how it is organized, and what job a particular sentence does.
Also known as: main purpose questions, function of a sentence, overall structure.
Key ideas
- Purpose = why the author wrote it; structure = how the ideas are ordered; function = what one sentence contributes.
- Describe each sentence's role in a few words before reading the choices.
- Wrong answers are often true about one detail but don't describe the text as a whole.
Map the text
Give each sentence a short label: claim, example, contrast, evidence, conclusion. A text that reads "Scientists believed X. However, new evidence shows Y. So they now think Z." has the structure old view → evidence → revised view.
Choosing the answer
Match your map to the choices. Watch the verbs: argue, describe, challenge, explain. A text that only reports a finding doesn't argue; a text that adds a limitation qualifies rather than rejects a claim.
Worked examples
Example 1 · Overall structure
For years, scientists believed dinosaurs were cold-blooded. Studies of bone growth, however, show many grew rapidly, a trait of warm-blooded animals. Many researchers now think dinosaur metabolism was closer to birds'.
- Step 1.Sentence 1: older view. Sentence 2: contrary evidence. Sentence 3: revised view.
Answer: It presents an older view, describes evidence against it, and states a revised view.
Example 2 · Function of a sentence
Most volcanoes form where tectonic plates meet. The Hawaiian Islands, however, lie in the middle of the Pacific Plate. Scientists explain this with a 'hot spot' of rising material.
- Step 1.However marks sentence 2 as an exception to the general rule in sentence 1.
Answer: It introduces an exception to the pattern stated in the first sentence.
Common mistakes
- Choosing an answer that describes only one sentence when the question asks about the whole text.
- Overstating the author's position ("rejects" when the text only "qualifies").
- Ignoring signal words like however, as a result and for example.
Try it yourself
Original practice questions. Your answer is checked instantly.
Which choice best states the main purpose of the text?
Which choice best describes the overall structure of the text?