Narrator: Listen to part of a lecture in an environmental science class. Professor: Today we’re talking about urban heat islands, where cities are significantly warmer than surrounding rural areas. This happens because concrete and asphalt absorb and re-radiate heat, while vegetation, which provides shade and releases moisture, is scarce. One surprising solution? Green roofs—rooftops covered with plants. A study in Chicago found that green roofs can lower rooftop surface temperatures by up to 40 degrees Fahrenheit on hot days, reducing the need for air conditioning. But the benefits go beyond temperature. They also absorb rainwater, reducing runoff and strain on sewer systems. Moreover, green roofs provide habitats for birds and insects in dense urban areas. However, they require careful engineering to support the weight of soil and plants, and they need regular maintenance, especially during dry periods. So, while initial costs are higher than traditional roofs, the long-term energy savings and environmental benefits often justify the investment. Does anyone have a question?
❓ Question What is the main topic of the lecture?
A. The disadvantages of urban development
B. The function and benefits of green roofs
C. The history of roof construction techniques
D. The effects of climate change on agriculture
✅ Correct Answer
The function and benefits of green roofs
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
