Question 141·Hard·Central Ideas and Details
During the last decade, several North American cities have begun “daylighting” once-buried streams—removing them from underground culverts and allowing them to flow again on the surface. Urban planners argue that these revived waterways reduce flooding by giving stormwater a place to spread out, while biologists note the rapid return of native plants and insects to newly exposed banks. Neighborhood groups, meanwhile, report increased foot traffic to adjoining parks and credit the projects with strengthening local businesses. Although opponents worry about short-term construction costs and traffic detours, supporters counter that the environmental and social gains will outweigh these inconveniences.
Which choice best states the main idea of the text?
For main idea questions, read the entire passage, then briefly summarize in your own words what the author is mainly doing (for example, “describing a practice and why many see it as beneficial despite some drawbacks”). Next, eliminate answer choices that focus on only one small detail, introduce new information (like “most residents” or a “disagreement” that the text never mentions), or reverse the passage’s overall tone. Finally, pick the option that matches your summary and includes both sides of any key contrast the passage makes, such as benefits vs. costs.
Hints
Start with the first and last sentences
Look closely at what the first sentence introduces and what the last sentence emphasizes. How do they frame the whole discussion about daylighting streams?
Look for what most groups agree on
Urban planners, biologists, and neighborhood groups are all mentioned. What overall pattern do their comments share about daylighted streams?
Compare benefits and drawbacks
The passage mentions both positive outcomes and some concerns. Which answer choice reflects both the positive impacts and the short-term problems mentioned?
Step-by-step Explanation
Identify the general topic of the passage
Read the first sentence: it introduces the practice of "daylighting" buried streams in North American cities. This tells you the passage is about a specific kind of urban project and what it involves, not about something else like transportation or business alone.
Notice the different groups and their perspectives
The passage then lists several groups and what they say:
- Urban planners: say that revived waterways reduce flooding.
- Biologists: point out the return of native plants and insects.
- Neighborhood groups: mention increased park foot traffic and stronger local businesses. These are all positive effects from different angles (environmental and community). Keep in mind that a correct main-idea answer should cover all of these, not just one.
Pay attention to the contrast with opponents
The last sentence starts with "Although opponents worry about short-term construction costs and traffic detours" and then contrasts this with supporters who say "environmental and social gains will outweigh these inconveniences." This contrast is crucial: it shows there are some temporary problems, but supporters think the long-term benefits are greater. The main idea must reflect both the benefits and the fact that there are costs or disruptions.
Match the choice that covers benefits vs. temporary costs
Now compare the answer choices to what the passage mainly does: it describes how various groups see environmental and community benefits from daylighting, while acknowledging short-term costs and inconveniences that supporters believe will be outweighed. Only choice D, “Cities that restore buried streams expect long-term environmental and community benefits to justify the projects’ temporary costs and disruptions,” captures both the broad range of benefits and the idea that these benefits justify the short-term problems.