Reading Comprehension: Main Idea and Purpose
What the question is really asking
Main-idea questions ask what the passage is about as a whole; purpose questions ask why the writer produced it (to inform, persuade, compare, warn, entertain, recommend). Both require you to weigh the entire text, not one vivid sentence.
Concepts to master
- Topic vs. thesis: the topic is the subject (e.g., urban cycling); the thesis is the claim the writer makes about it (e.g., protected lanes reduce accidents more than helmet campaigns).
- Text type signals: a title plus a date and figures suggests an informative report; rhetorical questions and imperatives suggest persuasion; first-person anecdotes suggest a column or personal essay.
- Structural cues: the opening and closing paragraphs usually carry the thesis; contrast connectors (however, yet, en revanche) often mark the writer's real position.
- Scope: the correct answer covers the whole passage. Answers that are too narrow (one paragraph) or too broad (all of environmental policy) are wrong.
Traps to expect
- A true detail offered as the main idea.
- An overgeneralised statement using absolute words (always, never, all).
- A purpose answer that describes the topic rather than the writer's aim.
- A moral or opinion the writer never actually states.
Rule of thumb
Before reading the options, write a one-sentence summary in your own words: The writer wants to convince readers that X because Y. Then choose the option closest to it; if two options seem right, the correct one is the one covering more of the text without adding claims.
Worked example
A passage describes a town's bike-lane trial, notes a 30% drop in collisions, then argues the council should make the lanes permanent. The main idea is not "bike lanes reduce collisions" (a supporting detail) but "the trial's results justify making the lanes permanent". The purpose is to persuade the council.