GRE Reading Comprehension:
distinguish main idea, function, and inference

In GRE Reading Comprehension, the main idea summarizes the passage, a function question asks what a sentence does, and an inference must be supported by the text. For each choice, find textual evidence and check its scope. This Upsilar workshop includes two fictional passages in English and four worked questions.

Article · 4 min read · 1 source ETS · verified on October 15, 2026 · free, no account needed

Map the passage

You do not need to translate every word when previewing a passage. Look for who is speaking, which idea is being examined, and what changes in the final sentence. A sentence may present another researcher’s view without the author endorsing it. Track these shifts in voice: a reported viewpoint, an objection, or the position the author adopts.

Next, identify what the question asks. A main-idea question calls for an answer that covers the passage’s overall development; a function question asks what a sentence does in the argument; an inference requires one additional step, still supported by the text. A scientifically true statement is not enough if it answers a different question.

Passage A: an observation and its limitation

Upsilar workshop: fictional scenario. Sentence numbers are included only to support the instructional explanations.

(1) City planners often treat the number of people entering a public garden as a measure of its success. (2) After a small garden installed additional benches, visits increased, but the average length of each visit fell. (3) Interviews revealed that commuters had begun using the garden as a shortcut, while its regular visitors continued to stay as long as before. (4) The higher visitor count therefore did not, by itself, establish that the garden had become a more attractive place to rest.

Main idea

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Which statement best captures the main point of Passage A?

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The solution, step by step

B.

The method in action

  1. The conclusion limits how the visitor count should be interpreted; B covers both the observation and the qualification.
  2. A turns the shortcut into a goal of the planners, which the passage does not say. C claims regular visitors stayed for less time, contrary to sentence 3. D makes an unsupported general prohibition. E claims the benches caused the change, which the passage does not establish.

Function of sentence 3

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What role does sentence 3 play in Passage A?

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The solution, step by step

D.

The method in action

  1. The interviews help explain the contrast between more entries and a shorter average visit.
  2. A reverses the idea: the sentence does not dismiss the observations. B invents a recommendation. C claims visits lasted longer, which is not stated. E concerns cost, which is never mentioned.

Passage B: a qualified conclusion

Upsilar workshop: fictional scenario.

In a digitization project, a museum photographed every page of a set of handwritten notebooks. The resulting images preserved marginal notes that earlier typed transcripts had omitted. However, faded ink was often difficult to read in the photographs. The curator therefore described the images as a valuable supplement to the transcripts, rather than a complete replacement for them.

Inference

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Which conclusion is best supported by Passage B?

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The solution, step by step

A.

The method in action

  1. Images and transcripts may provide complementary information: the images preserve marginal notes, while the transcripts may help when the ink in a photograph is hard to read.
  2. B generalizes a difficulty that occurs often but not always. C contradicts “every page.” D turns a supplement into an exclusive replacement. E invents a comparison between the legibility of the originals and every photograph.

Vocabulary in context

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In Passage B, “supplement” most nearly means which of the following?

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The solution, step by step

C — an addition that provides further material.

The method in action

  1. The contrast with replacement defines supplement as an additional resource.
  2. A summary may replace details, a duplicate repeats something, and a review evaluates it; none fits the role described. The word also does not mean a repair to the originals.

The pitfall

The pitfall to avoid

Choosing an answer because it repeats words from the passage is a mistake. An option may mention benches or photographs while reversing a relationship. Check the subject, verb, scope, and quantifiers: some, all, may, and must are not interchangeable.

Make every choice verifiable

For each correct answer, find the sentence that supports it and identify the logical relationship involved. For each incorrect choice, name one flaw: contradiction, overgeneralization, irrelevant detail, or unsupported addition. This is more instructive than saying “this answer sounds better.” ETS says the passages do not require specialized outside knowledge.

Finally, reread the passage without the questions and summarize it in one sentence. If your summary omits the final qualification, you may choose an answer that is too broad for the main idea. If you remember only the examples, you may confuse supporting evidence with the thesis.

Key takeaways

  • Distinguish the author’s voice from reported ideas.
  • Identify what the question asks before comparing the choices.
  • Support each inference with textual evidence.
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