Question 103·Easy·Central Ideas and Details
During a recent locust outbreak in northern provinces, entomologist Lin Wei investigated a naturally occurring soil fungus that infects insects. In controlled field trials, the fungus killed locust nymphs within 48 hours and produced airborne spores that traveled to nearby swarms. Wei says the results indicate that the fungus could reduce reliance on chemical pesticides while keeping locust populations in check.
Which choice best states the main idea of the text?
For main-idea questions on the SAT, first restate the passage in 1–2 simple sentences without looking at the choices. Then, compare each option to your summary and eliminate any that (1) focus on a minor detail instead of the overall point, (2) add information or attitudes not in the text, or (3) contradict what the author clearly states. Finally, pick the choice that best matches the author’s overall conclusion or purpose, often found near the end of a short passage.
Hints
Use the conclusion
In short passages, the main idea is often stated or implied in the final sentence. Look at what Wei says the results indicate.
Include both key parts
Your main-idea summary should mention (1) the fungus’s effectiveness against locusts and (2) the implication about reducing chemical pesticide use.
Avoid detail-only or add-on claims
Eliminate choices that focus on just one detail (like crop damage or spore movement) or that add an attitude/claim (like calling it a “risk”) that the passage doesn’t state.
Step-by-step Explanation
Identify the task: main idea, not a detail
The question asks for the choice that best states the main idea of the text. This means you should look for an answer that captures what the entire passage is mostly about, not just one fact or a minor point.
Summarize the passage in your own words
Briefly restate the paragraph:
- Lin Wei studies a soil fungus that infects insects.
- In field trials, the fungus killed locust nymphs quickly (within 48 hours).
- It produced spores that spread to nearby locust swarms.
- Wei concludes that this fungus could help control locust populations and reduce the need for chemical pesticides.
So overall, the focus is on Wei’s research and what it suggests about using the fungus to manage locusts with less pesticide use.
Match that summary to the answer choices
Now compare your summary to each option:
- Eliminate choices that focus on crop damage or other background information the passage does not emphasize.
- Eliminate choices that add warnings or requirements (like needing close monitoring) that the passage never states.
- Eliminate choices that contradict the conclusion about reducing reliance on chemical pesticides.
- Keep the option that captures the research result and its implication for controlling locusts.
Confirm the best match
The choice that reflects the passage’s overall point—Wei’s trials indicate a natural fungus can kill locusts quickly and reduce reliance on chemical pesticides—is:
Lin Wei’s trials suggest a naturally occurring fungus can quickly kill locusts and reduce the need for chemical pesticides.