Narrator: Listen to part of a lecture in an environmental science class. Professor: Today we're going to talk about urban heat islands. As you know, cities tend to be warmer than surrounding rural areas. This is due to several factors. First, concrete and asphalt absorb and retain heat during the day, then release it slowly at night. Second, buildings and tall structures block wind, reducing natural cooling. Third, there's less vegetation, which means less shade and less evaporation from plants. One solution is to increase green spaces, like parks and green roofs. Green roofs are covered with plants, which can lower rooftop temperatures by as much as 30 degrees Celsius. They also reduce stormwater runoff and improve air quality. However, the initial cost of installing a green roof is higher than a traditional roof. But over time, the energy savings from reduced air conditioning use can offset that cost. Also, green roofs can extend the lifespan of the roof membrane. So, while the upfront investment is significant, the long-term benefits are substantial.
❓ Question What is the main topic of the lecture?
A. The causes and solutions of urban heat islands
B. The history of green roof technology
C. The economic costs of traditional roofing
D. The effects of wind on city temperatures
✅ Correct Answer
The causes and solutions of urban heat islands
TOEFL Listening Tips
Skim the questions first to predict the content
Watch for signal words in lectures and conversations (however, actually, in fact)
For main idea questions, focus on the beginning; for detail questions, focus on examples and data
For attitude questions, pay attention to the speaker's tone and word choice
Take notes on keywords; don't try to write down every word
