Which best describes a main idea in reading comprehension?

• A. The overall point the passage communicates.
• B. A random detail.
• C. The author's favorite color.
• D. The length of the passage.

Answer: (A)

The main idea is the overall point the passage communicates—the big message the author wants you to take away. It’s the idea that ties all the sentences and details together, not a single fact or a random piece of information. You’ll often see it as the claim the author develops through examples, reasoning, and evidence, and it can be stated outright or implied by how the details are organized.

To spot it, notice what the passage keeps returning to, what the author emphasizes the most, and what idea would summarize everything the passage explains or argues. The supporting details exist to illustrate or prove that central point, so they won’t stand alone as the main message.

Choice elements like a random detail, the author’s favorite color, or the length of the passage don’t describe the main idea. A random detail is only a part of the illustration, color or length are about incidental aspects, not about what the passage is communicating as a whole.