Reading: Main Ideas, Details, and Inference
What the Reading section tests
Reading items ask you to locate and interpret information in short passages. The core skills are identifying the main idea, distinguishing supporting details from minor ones, following a sequence of events, comparing and contrasting ideas, and drawing a reasonable inference supported by the text.
Concepts to master
- Main idea vs. topic: the topic is the subject ("the water cycle"); the main idea is the claim about it ("the water cycle redistributes heat and water across the planet").
- Explicit vs. implied: explicit details are stated; inferences are conclusions the text supports but does not state.
- Author's purpose and tone: is the passage explaining, persuading, or narrating? Tone words signal attitude.
- Vocabulary in context: a familiar word can shift meaning by surrounding clues.
Traps to watch
- True but off-topic answers - the statement is accurate but is not the main idea.
- Too broad or too narrow main-idea choices.
- Overreaching inferences - conclusions that go beyond what the passage supports.
- Extreme wording ("always," "never," "proves") in an answer choice when the passage is moderate.
Worked example
Passage: "Desert plants often store water in thick stems. Some open their pores only at night, when air is cooler and moisture loss is lower."
Question: What is the main idea?
- A) Desert plants are always green. (Unsupported)
- B) Desert plants have adaptations that conserve water. (Correct - both details support it)
- C) Night air is cooler than day air. (True detail, too narrow)
- D) Desert plants never need rain. (Extreme, unsupported)
Rule of thumb: if a choice is supported by only one sentence, it is likely a detail, not the main idea.