Question 153·Medium·Central Ideas and Details
Over the past decade, urban planners have begun planting dense stands of trees along city streets and on unused lots, creating what they call "urban forests." According to recent studies, these tree clusters cool surrounding neighborhoods by casting shade and releasing water vapor, lower residents’ stress levels, and even reduce asthma attacks by filtering pollutants from the air. Because of these documented benefits, several major cities have announced initiatives to expand their urban forests over the next five years.
Which choice best states the text’s main idea?
For main-idea questions, briefly restate what the passage is mostly doing (here: describing benefits and a resulting decision). Then choose the option that includes the central topic and the passage’s key takeaway, while eliminating choices that introduce comparisons, time frames, or claims not stated in the text.
Hints
Use the last sentence
Focus on the last sentence: it explains why cities are planning to expand urban forests.
Name the benefits
List the benefits mentioned (cooling and health-related effects). The main idea should include these.
Avoid added details
Cross out any answer that adds something not in the passage (preferences, strict time frames, or native vs. non-native comparisons).
Pick the broadest accurate summary
The correct choice should connect the benefits of urban forests to the cities’ decision to expand them.
Step-by-step Explanation
Identify the task
The question asks for the text’s main idea: the overall point of the entire passage, not a minor detail.
Summarize the passage
The passage says urban planners are creating “urban forests,” studies show these tree clusters cool neighborhoods and improve residents’ health, and therefore cities plan to expand them over the next five years.
Eliminate choices that add unsupported claims
Eliminate any option that introduces ideas the passage never states, such as people’s preferences about air conditioning, specific timelines about how long benefits take to appear, or claims that only native trees work better than non-native trees.
Select the choice that matches the full summary
The best answer is the choice stating that dense clusters of urban trees cool neighborhoods and improve health, so cities plan to expand urban forests.