27. RC main idea
Pre-answer before reading choices. Verb filter, umbrella test: covers all paragraphs, no more.
Core ideas
- Pre-answer: after reading, state the main point in your own words BEFORE looking at choices.
- Verb filter: the choice's verb must match what the passage does (argue, compare, describe, challenge).
- Umbrella test: the right answer covers every paragraph and nothing beyond the passage.
- Wrong answers are usually one paragraph's detail promoted to main idea, or the right scope with a distorted verb.
Worked example 1
Passage summary: Paragraph 1 describes the long-held view that the ancient city of Tessara declined because of drought. Paragraph 2 presents new sediment evidence suggesting rainfall was stable during the decline. Paragraph 3 proposes that shifting trade routes, not climate, drained the city's economy, while conceding the trade hypothesis needs more excavation to confirm.
Question: The primary purpose of the passage is to
(A) describe the sediment analysis techniques used at Tessara
(B) challenge a traditional explanation for a city's decline and propose a tentative alternative
(C) prove that trade routes caused Tessara's collapse
Show solution
Pre-answer first: the passage pushes back on the drought theory and floats a trade-based alternative, with hedging. Verb filter: the passage challenges and proposes; it does not merely describe techniques, and it does not prove anything (paragraph 3 explicitly hedges). Umbrella test: (B) covers all three paragraphs, the old view, the counterevidence, and the new hypothesis. (A) is one paragraph's detail promoted to main idea; (C) has the right topic but an overclaiming verb, since the author calls the alternative unconfirmed. Answer: (B).
Worked example 2
Passage summary: Paragraph 1 notes that two economists, Varga and Liu, agree that automation displaced factory jobs in the region of Caldonia. Paragraph 2 explains Varga's view that retraining programs largely offset the losses. Paragraph 3 presents Liu's data showing retraining helped only younger workers, leaving older workers persistently unemployed. The author does not take a side.
Question: The passage is primarily concerned with
(A) contrasting two economists' assessments of how well retraining offset automation-related job losses
(B) arguing that retraining programs fail older workers
(C) explaining why automation displaced factory jobs in Caldonia
Show solution
Pre-answer: the passage lays two views side by side about whether retraining worked. Verb filter: the author contrasts without arguing, so (B)'s verb "arguing" misattributes Liu's position to the author. Umbrella test: (C) covers only the shared premise in paragraph 1 and ignores the retraining debate that fills paragraphs 2 and 3. (A) spans all three paragraphs at the right altitude and matches the neutral, comparative stance. Answer: (A).
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