Sección 2: Section-Specific Tips

How to Find the Main Idea in Long Passages

7 min de lectura · Entrenau

On the ACT by ACT, Inc., many reading comprehension questions ask you to identify the main idea of a lengthy passage. It is not about reading every word with equal attention, but about using strategic techniques to locate the central theme quickly and accurately.

Where to Look for the Main Idea

In well-structured texts, the main idea is usually in the first or last sentence of the paragraph. In argumentative texts, look for the author's thesis — the claim the rest of the text tries to prove.

In informational texts, the title and first paragraph typically contain the central idea. In literary texts, the main idea may be implicit and require inference.

Speed Reading Technique

Read the title, the first paragraph, and the last paragraph. Then read the first sentence of each intermediate paragraph. With this information, you should be able to formulate the main idea without having read every detail.

This technique is especially useful when time is limited. It lets you answer main-idea questions in under 2 minutes.

Tip: Ask yourself: "What is this passage about in one sentence?" If you can answer that, you have the main idea.

Where to find the main idea by text type
Text typeMost common locationKey clue
ArgumentativeFirst or last paragraphLook for the thesis or conclusion
InformationalTitle + first paragraphSummarizes the central subject
NarrativeImplicit (infer)Ask what message the story conveys
ScientificIntroduction and conclusionLook for the hypothesis and results

Original content — Entrenau

Main Idea vs. Topic vs. Detail

The topic is the general subject (e.g., "pollution"). The main idea is what the author says about that topic (e.g., "urban pollution has decreased thanks to public policy"). Details are the evidence or examples that support the main idea.

On exam questions, make sure you distinguish among all three: the main idea is more specific than the topic but more general than a detail.

How to Practice

After each passage on a practice test, try to summarize the main idea in one sentence before looking at the answer choices. This trains your synthesis ability and protects you from distractors.

Read newspaper articles or essays and practice identifying the author's thesis. The more you read, the faster you will recognize patterns of text structure.

Fuentes: Official ACT website

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