English 11 / Unit 10: Test Skills for Reading and Writing
10.2 Central Idea and Purpose
Notes
Questions ask for the main idea or why the author wrote the passage or a part of it.
- The central idea covers the whole passage, not just one detail. Wrong choices are often too narrow, too broad, or extreme ("always," "never").
- The purpose is a verb: to inform, to argue, to describe, to challenge an assumption, to propose a solution.
- For a sentence's function, ask what job it does: gives an example, introduces a counterpoint, offers evidence.
- Worked example: A passage that gives three examples of rooftop gardens feeding neighborhoods has a main idea about the benefits of urban agriculture.
Practice
Passage: "City planners once saw empty rooftops as wasted space. Now, many cities encourage gardens on rooftops, where vegetables grow, rain is absorbed, and buildings stay cooler in summer. These small green spaces turn unused areas into useful ones." Which choice best states the main idea?
The passage lists benefits of converting unused rooftops.
Passage: "Many people believe that talent alone makes a great musician. But interviews with professional players tell a different story: nearly all describe years of daily, focused practice. Talent may open the door, but practice carries a musician through it." The author's primary purpose is to:
The author names a common belief and argues against it.
Passage: "The lighthouse stood on a windswept cliff. Its lamp had guided ships for over a century. Yet by 1990, satellites had replaced its beam, and the keeper's cottage fell silent." The final sentence mainly serves to:
"Yet" signals a change; the sentence shows the lighthouse was replaced.
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